High expression of ALDH1A3 might independently influence poor progression‐free and overall survival in patients with glioma via maintaining glucose uptake and lactate production

Recent studies have found that the acetaldehyde dehydrogenase 1A3 (ALDH1A3) gene is a marker of glioma stem cells. A total of 115 brain glioma specimens were collected and classified into grade I–IV, while non‐tumor brain tissue specimens, taken from 12 patients of vascular malformation surgery, were used as control. ALDH1A3 gene promoter methylation in glioma tissues was detected by pyrosequencing, while immunohistochemistry and western blot were used to detect ALDH1A3 protein expressions in different grades of glioma tissues and normal brain tissues. The expression of ALDH1A3 in the glioma cell line U87 was detected by quantitative real‐time polymerase chain reaction and RNA‐Seq technology was applied to investigate differentially expressed genes before and after silencing the ALDH1A3 gene. Among the 115 glioma tissue specimens, 50 (43.48%) showed low and 65 (56.52%) high expression of ALDH1A3, but no expression was detected in the control. Univariate and multivariate COX regression analyses showed that the patient's tumor pathological grade, the methylation status of ALDH1A3 promoter, and the expression of ALDH1A3 protein were risk factors for progression‐free survival (PFS) and overall survival (OS) (all P < 0.05) and the OS of mice with silenced ALDH1A3 in a glioma nude mouse model was prolonged. U87 experiments revealed that ALDH1A3 expression had significant effects on apoptosis, proliferation, cell cycle, mitochondrial membrane potential, glucose consumption, lactate production, invasion ability, and expression of the pyruvate kinase M2 (PKM2) and hexokinase 2 (HK2) in glioma cells. ALDH1A3 protein expression is a marker for poor PFS and OS in glioma patients.     

Aldehyde dehydrogenase 3B2 promotes the proliferation and invasion of cholangiocarcinoma by increasing Integrin Beta 1 expression

Aldehyde dehydrogenases (ALDHs) play an essential role in regulating malignant tumor progression; however, their role in cholangiocarcinoma (CCA) has not been elucidated. We analyzed the expression of ALDHs in 8 paired tumor and peritumor perihilar cholangiocarcinoma (pCCA) tissues and found that ALDH3B1 and ALDH3B2 were upregulated in tumor tissues. Further survival analysis in intrahepatic cholangiocarcinoma (iCCA, n = 27), pCCA (n = 87) and distal cholangiocarcinoma (dCCA, n = 80) cohorts have revealed that ALDH3B2 was a prognostic factor of CCA and was an independent prognostic factor of iCCA and pCCA. ALDH3B2 expression was associated with serum CEA in iCCA and dCCA, associated with tumor T stage, M stage, neural invasion and serum CA19-9 in pCCA. In two cholangiocarcinoma cell lines, overexpression of ALDH3B2 promoted cell proliferation and clone formation by promoting the G1/S phase transition. Knockdown of ALDH3B2 inhibited cell migration, invasion, and EMT in vitro, and restrained tumor metastasis in vivo. Patients with high expression of ALDH3B2 also have high expression of ITGB1 in iCCA, pCCA, and dCCA at both mRNA and protein levels. Knockdown of ALDH3B2 downregulated the expression of ITGB1 and inhibited the phosphorylation level of c-Jun, p38, and ERK. Meanwhile, knockdown of ITGB1 inhibited the promoting effect of ALDH3B2 overexpression on cell proliferation, migration, and invasion. ITGB1 is also a prognostic factor of iCCA, pCCA, and dCCA and double-positive expression of ITGB1 and ALDH3B2 exhibits better performance in predicting patient prognosis. In conclusion, ALDH3B2 promotes tumor proliferation and metastasis in CCA by regulating the expression of ITGB1 and upregulating its downstream signaling pathway. The double-positive expression of ITGB1 and ALDH3B2 serves as a better prognostic biomarker of CCA.Subject terms: Prognostic markers, Bile duct cancer     

Knockdown of FRAT1 Expression by RNA Interference Inhibits Human Glioblastoma Cell Growth,Migration and Invasion

Background

FRAT1 positively regulates the Wnt/β-catenin signaling pathway by inhibiting GSK-3-mediated phosphorylation of β-catenin. It was originally characterized as a protein frequently rearranged in advanced T cell lymphoma, but has recently also been identified as a proto-oncogene involved in tumorigenesis. Our previous studies showed that FRAT1 was dramatically overexpressed in gliomas and its expression level was significantly increased along with clinicopathological grades.

Methods

In the current study, we used RT-PCR and Western blotting to assess the mRNA and protein levels of FRAT1 in three glioma cell lines. In addition, to evaluate its functional role in gliomas, we examined the effects of FRAT1 knockdown on proliferation, migration and invasion in vitro and tumor growth in vivo using glioblastoma U251 cells and RNAi.

Results

FRAT1 was highly expressed in all three glioma cell lines. RNAi-mediated down-regulation of endogenous FRAT1 in human glioblastoma U251 cells resulted in suppression of cell proliferation, arrest of cell cycle, inhibition of cell migration and invasion in vitro. Moreover, FRAT1 depletion significantly impaired tumor xenograft growth in nude mice.

Conclusions

Our results highlight the potential role of FRAT1 in tumorigenesis and progression of glioblastoma. These findings provide a biological basis for FRAT1 as a potential molecular marker for improved pathological grading and as a novel candidate therapeutic target for glioblastoma management.     

MEX3A promotes the malignant progression of ovarian cancer by regulating intron retention in TIMELESS

The latest research shows that RNA-binding proteins (RBPs) could serve as novel potential targets for cancer therapy. We used bioinformatics analysis to screen and identify the key RBPs in ovarian cancer, from which we found that Mex-3 RNA Binding Family Member A (MEX3A) was intimately associated with the clinical prognosis of ovarian cancer. Nevertheless, little is known about its biological roles in ovarian cancer. In this case, we observed that MEX3A was highly overexpressed in fresh-frozen ovarian cancer tissues. MEX3A knockdown suppressed the development and invasion of ovarian cancer cells, while MEX3A overexpression promoted the proliferation and invasion of ovarian cancer cells. Mechanistically, TIMELESS was the critical downstream target gene of MEX3A, as demonstrated through alternative splicing event analysis based on RNA-seq. MEX3A knockdown resulted in retention of intron twenty-three of TIMELESS mRNA and decreased TIMELESS mRNA owing to stimulation of nonsense-mediated RNA decay (NMD). Additionally, we found that TIMELESS overexpression with MEX3A knockdown partially restored the proliferation ability of ovarian cancer cells. The results of this paper demonstrated that the MEX3A/TIMELESS signaling pathway was a key regulator of ovarian cancer, and MEX3A was a novel possible treatment target for ovarian cancer patients.Subject terms: Ovarian cancer, Ovarian cancer     

lncRNA A1BG-AS1 suppresses proliferation and invasion of hepatocellular carcinoma cells by targeting miR-216a-5p

Extensive evidence indicate that long noncoding RNAs (lncRNAs) regulates the tumorigenesis and progression of hepatocellular carcinoma (HCC). However, the expression and biological function of lncRNA A1BG antisense RNA 1 (A1BG-AS1) were poorly known in HCC. Here, we found the underexpression of A1BG-AS1 in HCC via analysis of The Cancer Genome Atlas database. Further analyses confirmed that A1BG-AS1 expression in HCC was markedly lower than that in noncancerous tissues based on our HCC cohort. Clinical association analysis revealed that low A1BG-AS1 expression correlated with poor prognostic features, such as microvascular invasion, high tumor grade, and advanced tumor stage. Follow-up data indicated that low A1BG-AS1 level evidently correlated with poor clinical outcomes of HCC patients. Moreover, forced expression of A1BG-AS1 repressed proliferation, migration, and invasion of HCC cells in vitro. Conversely, A1BG-AS1 knockdown promoted these malignant behaviors in HepG2 cells. Mechanistically, A1BG-AS1 functioned as a competing endogenous RNA by directly sponging miR-216a-5p in HCC cells. Notably, miR-216a-5p restoration rescued A1BG-AS1 attenuated proliferation, migration and invasion of HCCLM3 cells. A1BG-AS1 positively regulated the levels of phosphatase and tensin homolog and SMAD family member 7, which were reduced by miR-216a-5p in HCC cells. Altogether, we conclude that A1BG-AS1 exerts a tumor suppressive role in HCC progression.     

NKCC1 promotes EMT-like process in GBM via RhoA and Rac1 signaling pathways

Glioblastoma is the most common and lethal primary intracranial tumor. As the key regulator of tumor cell volume, sodium-potassium-chloride cotransporter 1 (NKCC1) expression increases along with the malignancy of the glioma, and NKCC1 has been implicated in glioblastoma invasion. However, little is known about the role of NKCC1 in the epithelial-mesenchymal transition-like process in gliomas. We noticed that aberrantly elevated expression of NKCC1 leads to changes in the shape, polarity, and adhesion of cells in glioma. Here, we investigated whether NKCC1 promotes an epithelial–mesenchymal transition (EMT)-like process in gliomas via the RhoA and Rac1 signaling pathways. Pharmacological inhibition and knockdown of NKCC1 both decrease the expressions of mesenchymal markers, such as N-cadherin, vimentin, and snail, whereas these treatments increase the expression of the epithelial marker E-cadherin. These findings indicate that NKCC1 promotes an EMT-like process in gliomas. The underlying mechanism is the facilitation of the binding of Rac1 and RhoA to GTP by NKCC1, which results in a significant enhancement of the EMT-like process. Specific inhibition or knockdown of NKCC1 both attenuate activated Rac1 and RhoA, and the pharmacological inhibitions of Rac1 and RhoA both impair the invasion and migration abilities of gliomas. Furthermore, we illustrated that NKCC1 knockdown abolished the dissemination and spread of glioma cells in a nude mouse intracranial model. These findings suggest that elevated NKCC1 activity acts in the regulation of an EMT-like process in gliomas, and thus provides a novel therapeutic strategy for targeting the invasiveness of gliomas, which might help to inhibit the spread of malignant intracranial tumors.     

Lipid Peroxidation Plays an Important Role in Chemotherapeutic Effects of Temozolomide and the Development of Therapy Resistance in Human Glioblastoma

BACKGROUND: Glioblastoma (GBM) is the most malignant primary brain tumor. Relapse occurs regularly, and the clinical behavior seems to be due to a therapy-resistant subpopulation of glioma-initiating cells that belong to the group of cancer stem cells. Aldehyde dehydrogenase (ALDH) has been identified as a marker for this cell population, and we have shown previously that ALDH1A3-positive GBM cells are more resistant against temozolomide (TMZ) treatment. However, it is still unclear how ALDH expression mediates chemoresistance. MATERIALS AND METHODS: ALDH1A3 expression was analyzed in 112 specimens from primary and secondary surgical resections of 56 patients with GBM (WHO grade IV). All patients received combined adjuvant radiochemotherapy. For experimental analysis, CRISPR-Cas9–induced knockout cells from three established GBM cell lines (LN229, U87MG, T98G) and two glioma stem-like cell lines were investigated after TMZ treatment. RESULTS: ALDH1A3 knockout cells were more sensitive to TMZ, and oxidative stress seemed to be the molecular process where ALDH1A3 exerts its role in resistance against TMZ. Oxidative stress led to lipid peroxidation, yielding active aldehydes that were detoxified by ALDH enzymatic activity. During the metabolic process, autophagy was induced leading to downregulation of the enzyme, but ALDH1A3 is upregulated to even higher expression levels after finishing the TMZ therapy in vitro. Recurrent GBMs show significantly higher ALDH1A3 expression than the respective samples from the primary tumor, and patients suffering from GBM with high ALDH1A3 expression showed a shorter median survival time (12 months vs 21 months, P < .05). CONCLUSION: Oxidative stress is an important and clinically relevant component of TMZ-induced therapeutic effects. Cytotoxicity seems to be mediated by aldehydes resulting from lipid peroxidation, and ALDH1A3 is able to reduce the number of toxic aldehydes. Therefore, we present a molecular explanation of the role of ALDH1A3 in therapeutic resistance of human GBM cells.     

Long non-coding ROR promotes the progression of papillary thyroid carcinoma through regulation of the TESC/ALDH1A1/TUBB3/PTEN axis

Papillary thyroidal carcinoma (PTC) is a common endocrine cancer that plagues people across the world. The potential roles of long non-coding RNAs (lncRNAs) in PTC have gained increasing attention. In this study, we aimed to explore whether lncRNA ROR affects the progression of PTC, with the involvement of tescalcin (TESC)/aldehyde dehydrogenase isoform 1A1 (ALDH1A1)/βIII-tubulin (TUBB3)/tensin homolog (PTEN) axis. PTC tumor and adjacent tissues were obtained, followed by measurement of lncRNA ROR and TESC, ALDH1A1, and TUBB3 expression. Interactions among lncRNA ROR, TESC, ALDH1A1, TUBB3, and PTEN were evaluated by ChIP assay, RT-qPCR, or western blot analysis. After ectopic expression and depletion experiments in PTC cells, MTT and colony formation assay, Transwell assay, and flow cytometry were performed to detect cell viability and colony formation, cell migration and invasion, and apoptosis, respectively. In addition, xenograft in nude mice was performed to test the effects of lncRNA ROR and PTEN on tumor growth in PTC in vivo. LncRNA ROR, TESC, ALDH1A1, and TUBB3 were highly expressed in PTC tissues and cells. Overexpression of lncRNA ROR activated TESC by inhibiting the G9a recruitment on the promoter of TESC and histone H3-lysine 9me methylation. Moreover, TESC upregulated ALDH1A1 expression to increase TUBB3 expression, which then reduced PTEN expression. Overexpression of lncRNA ROR, TESC, ALDH1A1 or TUBB3 and silencing of PTEN promoted PTC cell viability, colony formation, migration, and invasion while suppressing apoptosis. Moreover, overexpression of lncRNA ROR increased tumor growth by inhibiting PTEN in vivo. Taken together, the current study demonstrated that lncRNA ROR mediated TESC/ALDH1A1/TUBB3/PTEN axis, thereby facilitating the development of PTC.Subject terms: Gynaecological cancer, Cell biology     

Identification of COL6A1 as a differentially expressed gene in human astrocytomas

Diffuse infiltrating gliomas are the most common tumors of the central nervous system. Gliomas are classified by the WHO according to their histopathological and clinical characteristics into four classes: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). Several genes have already been correlated with astrocytomas, but many others are yet to be uncovered. By analyzing the public SAGE data from 21 patients, comprising low malignant grade astrocytomas and glioblastomas, we found COL6A1 to be differentially expressed, confirming this finding by real time RT-PCR in 66 surgical samples. To the best of our knowledge, COL6A1 has never been described in gliomas. The expression of this gene has significantly different means when normal glia is compared with low-grade astrocytomas (grades I and II) and high-grade astrocytomas (grades III and IV), with a tendency to be greater in higher grade samples, thus rendering it a powerful tumor marker.     

Negative regulation of the murine cytosolic aldehyde dehydrogenase-3 (Aldh-3c) gene by functional CYP1A1 and CYP1A2 proteins.

We have examined enzyme activities and mRNA levels corresponding to aldehyde dehydrogenase-3 genes encoding cytosolic (ALDH3c) and microsomal (ALDH3m) forms. In contrast to negligible activities in the intact mouse liver, both ALDH3c and ALDH3m enzyme activities are inducible by benzo[a]pyrene and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mouse hepatoma Hepa-1c1c7 cell cultures. Constitutive mRNA levels of ALDH3c are virtually absent, whereas those of ALDH3m are substantial; using Hepa-1 mutant lines, we show that both ALDH3c and ALDH3m are TCDD-inducible by an Ah receptor-dependent mechanism. Basal mRNA levels of ALDH3c, but not those of ALDH3m, are strikingly elevated in untreated mutant cells lacking a functional CYP1A1 enzyme; low ALDH3c basal mRNA levels can be restored by introduction of a functional murine CYP1A1 or human CYP1A2 enzyme into these mutant cells. These data suggest that the TCDD induction process is distinct from the CYP1A1/CYP1A2 metabolism-dependent repression of constitutive gene expression; we suggest that this latter property classifies the Aldh-3c gene, but not the Aldh-3m gene, as a member of the murine [Ah] battery.     

Distinct expression patterns and roles of aldehyde dehydrogenases in normal oral mucosa keratinocytes: differential inhibitory effects of a pharmacological inhibitor and RNAi-mediated knockdown on cellular phenotype and epithelial morphology

Aldehyde dehydrogenases (ALDHs), enzymes responsible for detoxification and retinoic acid biosynthesis, are considered a potent functional stem cell marker of normal and malignant cells in many tissues. To date, however, there are no available data on ALDH distributions and functions in oral mucosa. This study aims to clarify the levels and types of ALDH expression using immunohistochemistry with accompanying mRNA expression as well as an ALDEFLUOR assay, and to assess phenotypic and histological changes after manipulation of the ALDH activity of oral keratinocytes to increase the potency of a tissue-engineered oral mucosa by a specific ALDH inhibitor, diethylaminobenzaldehyde (DEAB), together with small interfering RNA of ALDH1A3 and ALDH3A1. Results showed the mRNA and cytoplasmic protein expression of ALDH1A3 and ALDH3A1 to be mostly localized in the upper suprabasal layer although no ALDH1A1 immunoreaction was detected throughout the epithelium. Oral keratinocytes with high ALDH activity exhibited a profile of differentiating cells. By pharmacological inhibition, the phenotypic analysis revealed the proliferating cell-population shifting to a more quiescent state compared with untreated cells. Furthermore, a well-structured epithelial layer showing a normal differentiation pattern and a decrease in Ki-67 immunopositive basal cells was developed by DEAB incubation, suggesting a slower turnover rate efficient to maintain undifferentiated cells. Histological findings of a regenerated oral epithelium by ALDH1A3 siRNA were similar to those when treated with DEAB while ALDH3A1 siRNA eradicated the epithelial regenerative capacity. These observations suggest the effects of phenotypic and morphological alterations by DEAB on oral keratinocytes are mainly consequent to the inhibition of ALDH1A3 activity.     

CD90 is identified as a candidate marker for cancer stem cells in primary high-grade gliomas using tissue microarrays

Although CD90 has been identified as a marker for various kinds of stem cells including liver cancer stem cells (CSCs) that are responsible for tumorigenesis, the potential role of CD90 as a marker for CSCs in gliomas has not been characterized. To address the issue, we investigated the expression of CD90 in tissue microarrays containing 15 glioblastoma multiformes (GBMs), 19 WHO grade III astrocytomas, 13 WHO grade II astrocytomas, 3 WHO grade I astrocytomas and 8 normal brain tissues. Immunohistochemical analysis showed that CD90 was expressed at a medium to high level in all tested high-grade gliomas (grade III and GBM) whereas it was barely detectable in low-grade gliomas (grade I and grade II) and normal brains. Double immunofluorescence staining for CD90 and CD133 in GBM tissues revealed that CD133(+) CSCs are a subpopulation of CD90(+) cells in GBMs in vivo. Flow cytometry analysis of the expression of CD90 and CD133 in GBM-derived stem-like neurospheres further confirmed the conclusion in vitro. The expression levels of both CD90 and CD133 were reduced along with the loss of stem cells after differentiation. Furthermore, the limiting dilution assay demonstrated that the sphere formation ability was comparable between the CD90(+)/CD133(+) and the CD90(+)/CD133(-) populations of GBM neurospheres, which is much higher than that of the CD90(-)/CD133(-) population. We also performed double staining for CD90 and a vascular endothelial cell marker CD31 in tissue microarrays which revealed that the CD90(+) cells were clustered around the tumor vasculatures in high-grade glioma tissues. These findings suggest that CD90 is not only a potential prognostic marker for high-grade gliomas but also a marker for CSCs within gliomas, and it resides within endothelial niche and may also play a critical role in the generation of tumor vasculatures via differentiation into endothelial cells.     

Enhanced IMP3 Expression Activates NF-кB Pathway and Promotes Renal Cell Carcinoma Progression

Background

Insulin-like growth factor 2 mRNA binding protein 3 (IMP3) is expressed in metastatic and a subset of primary renal cell carcinoma (RCC). However, the role of IMP3 in RCC progression was poorly understood. We aim to uncover the mechanism of IMP3 in regulating clear cell RCC (CCRCC) progression and validate the prognostic significance of IMP3 in localized CCRCC.

Methods

Caki-1 cells stably overexpressing IMP3 and Achn cells with knockdown of IMP3 were analyzed for cell migration and invasion by Transwell assay. RNA-seq was used to profile gene expression in IMP3-expressing Caki-1 cells. A cohort of 469 localized CCRCC patients were examined for IMP3 expression by immunohistochemistry using tumor tissue array.

Results

IMP3 promoted Caki-1 cell migration and invasion, whereas knockdown of IMP3 by RNAi inhibited Achn cell migration and invasion. Enhanced IMP3 expression activated NF-кB pathway and through which, it functioned in promoting the RCC cell migration. IMP3 expression in localized CCRCC was found to be associated with higher nuclear grade, higher T stage, necrosis and sarcomatoid differentiation (p< 0.001). Enhanced IMP3 expression was correlated with shorter recurrence-free and overall survivals. Multivariable analysis validated IMP3 as an independent prognostic factor for localized CCRCC patients.

Conclusion

IMP3 promotes RCC cell migration and invasion by activation of NF-кB pathway. IMP3 is validated to be an independent prognostic marker for localized CCRCC.     

Arachidonic acid suppresses growth of human lung tumor A549 cells through down-regulation of ALDH3A1 expression

Expression of aldehyde dehydrogenase 3A1 (ALDH3A1) in certain normal and tumor cells is associated with protection against the growth inhibitory effect of reactive aldehydes generated during membrane lipid peroxidation. We found that human lung tumor (A549) cells, which express high levels of ALDH3A1 protein, were significantly less susceptible to the antiproliferative effects of 4-hydroxynonenal compared to human hepatoma HepG2 or SK-HEP-1 cells that lack ALDH3A1 expression. However, A549 cells became susceptible to lipid peroxidation products when they were treated with arachidonic acid. The growth suppression of A549 cells induced by arachidonic acid was associated with increased levels of lipid peroxidation and with reduced ALDH3A1 enzymatic activity, protein, and mRNA levels. Furthermore, arachidonic acid treatment of the A549 cells resulted in an increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma), whereas NF-kappaB binding activity was inhibited. Blocking PPARgamma using a selective antagonist, GW9662, prevented the arachidonic acid-mediated reduction of ALDH3A1 expression as well as the growth inhibition of A549 cells, suggesting the central role of PPARgamma in these phenomena. The increase in PPARgamma and the reduction in ALDH3A1 were also prevented by exposing cells to vitamin E concomitant with arachidonic acid treatment. In conclusion, our data show that the arachidonic acid-induced suppression of A549 cell growth is associated with increased lipid peroxidation and decreased ALDH3A1 expression, which may be due to activation of PPARgamma.     

MiR-410 regulates MET to influence the proliferation and invasion of glioma

MET, the receptor for hepatocyte growth factor receptor (HGF), has been reported to trigger multiple and sometimes opposing cellular responses in various types of tumor cells. It has been implicated in the regulation of tumor-cell survival, proliferation, angiogenesis, invasion and metastasis. However, the MET regulatory mechanism in glioma is not well known. MicroRNAs are a class of small noncoding RNAs that play important roles in a variety of biological processes including human cancers. In this study, we used computational and expressional analysis to identify that the 'seed sequence' of miR-410 matched the 3' UTR of the MET mRNA. Besides, the expression of miR-410 was inversely associated with MET in human glioma tissues. Using luciferase and western blot assay, we certified that miR-410 directly targeted MET in glioma cells. While restoring expression of miR-410 led to proliferation inhibition and reduced invasive capability in glioma cells. Furthermore, we showed that miR-410 played an important role in regulating MET-induced AKT signal transduction. While downregulation of MET by RNAi, we observed that MET knockdown resulted in effects similar to that with miR-410 transfection in glioma cells. Our findings suggest that miR-410, a direct regulator of MET, may function as a tumor suppressor in human gliomas.     

Androgen regulation of aldehyde dehydrogenase 1A3 (ALDH1A3) in the androgen-responsive human prostate cancer cell line LNCaP

Previous gene array data from our laboratory identified the retinoic acid (RA) biosynthesis enzyme aldehyde dehydrogenase 1A3 (ALDH1A3) as a putative androgen-responsive gene in human prostate cancer epithelial (LNCaP) cells. In the present study, we attempted to identify if any of the three ALDH1A/RA synthesis enzymes are androgen responsive and how this may affect retinoid-mediated effects in LNCaP cells. We demonstrated that exposure of LNCaP cells to the androgen dihydrotestosterone (DHT) results in a 4-fold increase in ALDH1A3 mRNA levels compared with the untreated control. The mRNA for two other ALDH1A family members, ALDH1A1 and ALDH1A2, were not detected and not induced by DHT in LNCaP cells. Inhibition of androgen receptor (AR) with both the antiandrogen bicalutamide and small interfering RNA for AR support that ALDH1A3 regulation by DHT is mediated by AR. Furthermore, specific inhibition of the extracellular signal-regulated kinase and Src family of kinases with PD98059 and PP1 supports that AR's regulation of ALDH1A3 occurs by the typical AR nuclear-translocation cascade. Consistent with an increase in ALDH1A3 mRNA, DHT-treated LNCaP cells showed an 8-fold increase in retinaldehyde-dependent NAD(+) reduction compared with control. Lastly, treatment of LNCaP with all-trans retinal (RAL) in the presence of DHT resulted in significant up-regulation of the RA-inducible, RA-metabolizing enzyme CYP26A1 mRNA compared with RAL treatment alone. Taken together, these data suggest that (i) the RA biosynthesis enzyme ALDH1A3 is androgen responsive and (ii) DHT up-regulation of ALDH1A3 can increase the oxidation of retinal to RA and indirectly affect RA bioactivity and metabolism.     

Knockdown of SLC34A2 inhibits cell proliferation,metastasis, and elevates chemosensitivity in glioma

Solute carrier 34 A2 (SLC34A2) is a member of SLC34 family that is a group of phosphate transporters. SLC34A2 has been reported to play critical roles in tumorigenesis and progression. However, the researches about the biological roles of SLC34A2 in glioma have not yet been reported. In this study, we analyzed the expression patterns of SLC34A2 in clinical glioma tumor tissues and cell lines. The results demonstrated that SLC34A2 was generally overexpressed in both glioma tissues and cell lines. To further investigate the roles of SLC34A2 in glioma, lentivirus containing specific SLC34A2 short hairpin RNA (sh-SLC34A2) was used to infect glioma cell lines U251 and U87 for the knockdown of SLC34A2. The following studies proved that SLC34A2 knockdown exhibited suppressive effects on cell proliferation and migration/invasion. SLC34A2 knockdown also inhibited epithelial-mesenchymal transition (EMT) phenotype, as evidenced by the increased E-cadherin expression, and the decreased N-cadherin and fibronectin expressions. Besides, knockdown of SLC34A2 enhanced the temozolomide (TMZ) sensitivity of U251 and U87 cells. In vivo tumorigenicity assay demonstrated that SLC34A2 knockdown inhibited tumor growth. Moreover, SLC34A2 knockdown suppressed the activation of epidermal growth factor receptor (EGFR)/PI3K/AKT signaling pathway in U87 cells. GW2974 (EGFR inhibitor) increased SLC34A2 knockdown-inhibited cell proliferation, migration/invasion, as well as enhanced SLC34A2 knockdown-increased the TMZ sensitivity of glioma cells. These findings suggested that SLC34A2 might be a new potential therapeutic target for the therapy of glioma patients.     

NAMPT,GRN, and SERPINE1 signature as predictor of disease progression and survival in gliomas

Adipose tissue is an important source of adipokines involved in anti- and pro-inflammatory effects. Their involvement in certain cancers such as breast and colon cancer is known but in gliomas it remains unexplored till date. The aim of this study was to assess the status of adipokines as prognostic markers of gliomas (low grade gliomas [LGG] and glioblastoma mutiforme [GBM]). Expression status (messenger RNA [mRNA]), overall survival (OS) and disease-free survival (DFS) was identified using gene expression profiling interactive analysis server. Clinicopathological analysis and correlation between different adipokines was performed using Xena server. Protein expression status was analyzed using tissue sections from the Human Protein Atlas. Out of 11 adipokines studied visfatin (NAMPT), apelin (APLN), granulin (GRN), serpin peptidase inhibitor/plasminogen activator inhibitor type 1 (PAI-1) member 1 (SERPINE1), and chemokine (C-C motif) ligand 2 (CCL2) mRNA levels were significantly upregulated in both LGG and GBM. Interleukin 6 (IL6) mRNA was found be significantly upregulated only in GBM. NAMPT, GRN, SERPINE1, and IL6 showed reduced OS as well as worst DFS for patients having higher mRNA expression in LGG. Increased expression of CCL2 showed worst OS in LGG patients while resistin (RETN) and GRN showed the worst OS in GBM patients. Higher expression of RETN, GRN, IL6, SERPINE1, and CCL2 were found to be positively correlated with shorter DFS in GBM. In the clinicopathological analysis, NAMPT, GRN, IL6, SERPINE1, and CCL2 expressions were significantly associated between the neoplasm histological G2 and G3 grades. Furthermore, expression of NAMPT, GRN, tumor necrosis factor, IL6, SERPINE1, and CCL2 were significantly associated with histological type in LGG patients. NAMPT, GRN, SERPINE1, CCL2, and RETN expression were found to be correlated with each other in gliomas. Finally, NAMPT, GRN, and SERPINE1 were also found to be upregulated using immunohistochemistry in a lower grade and high grade gliomas as compared to normal cells. In conclusion, we have identified key adipokines, namely NAMPT, GRN, and SERPINE1 as potential diagnostic and prognostic markers that might be instrumental in the development and progression of gliomas.