Elevated AKR1C3 expression promotes prostate cancer cell survival and prostate cell-mediated endothelial cell tube formation: implications for prostate cancer progression

Regulatory effects of statins on Akt signaling for prevention of cancers

Statins, which are primarily used as lipid-lowering drugs, have been found to exhibit anti-tumor effects through modulating and interfering with various signaling pathways. In observational studies, statin use has been associated with a significant reduction in the progression of various cancers, including colon, lung, prostate, pancreas, and esophagus cancer, as well as melanoma and B and T cell lymphoma. The mevalonate pathway, which is affected by statins, plays a crucial role in activating Rho, Ras, and Rab proteins, thereby impacting the proliferation and apoptosis of tumor cells. Statins block this pathway, leading to the inhibition of isoprenoid units, which are critical for the activation of these key proteins, thereby affecting cancer cell behavior. Additionally, statins affect MAPK and Cdk2, which in turn reduce the expression of p21 and p27 cyclin-dependent kinase inhibitors. Akt signaling plays a crucial role in key cancer cell features like proliferation, invasion, and apoptosis by activating multiple effectors in downstream pathways such as FOXO, PTEN, NF-κB, GSK3β, and mTOR. The PI3K/Akt signaling is necessary for many events in the metastatic pathway and has been implicated in the resistance to cytostatic drugs. The Akt/PTEN axis is currently attracting great interest for its role in carcinogenesis. Statins have been shown to activate the purinergic receptor P2X7 and affect Akt signaling, which may have important anti-cancer effects. Hence, targeting Akt shows promise as an effective approach to cancer prevention and therapy. This review aims to provide a comprehensive discussion on the specific impact of statins through Akt signaling in different types of cancer.

AKR1C3 in carcinomas: from multifaceted roles to therapeutic strategies

Aldo-Keto Reductase Family 1 Member C3 (AKR1C3), also known as type 5 17β-hydroxysteroid dehydrogenase (17β-HSD5) or prostaglandin F (PGF) synthase, functions as a pivotal enzyme in androgen biosynthesis. It catalyzes the conversion of weak androgens, estrone (a weak estrogen), and PGD2 into potent androgens (testosterone and 5α-dihydrotestosterone), 17β-estradiol (a potent estrogen), and 11β-PGF2α, respectively. Elevated levels of AKR1C3 activate androgen receptor (AR) signaling pathway, contributing to tumor recurrence and imparting resistance to cancer therapies. The overexpression of AKR1C3 serves as an oncogenic factor, promoting carcinoma cell proliferation, invasion, and metastasis, and is correlated with unfavorable prognosis and overall survival in carcinoma patients. Inhibiting AKR1C3 has demonstrated potent efficacy in suppressing tumor progression and overcoming treatment resistance. As a result, the development and design of AKR1C3 inhibitors have garnered increasing interest among researchers, with significant progress witnessed in recent years. Novel AKR1C3 inhibitors, including natural products and analogues of existing drugs designed based on their structures and frameworks, continue to be discovered and developed in laboratories worldwide. The AKR1C3 enzyme has emerged as a key player in carcinoma progression and therapeutic resistance, posing challenges in cancer treatment. This review aims to provide a comprehensive analysis of AKR1C3's role in carcinoma development, its implications in therapeutic resistance, and recent advancements in the development of AKR1C3 inhibitors for tumor therapies.

ATM-Inhibitor AZD1390 Is a Radiosensitizer for Breast Cancer CNS Metastasis

PURPOSE

Limited effective treatments are currently available for central nervous system (CNS) metastasis (CM). This is largely driven by the inability of current therapeutics to penetrate the blood brain barrier (BBB) and the lack of preclinical models for testing new therapies. Here we study the efficacy of AZD1390, a BBB penetrating ataxia-telangiectasia mutated inhibitor, as a radiosensitizer for breast cancer CM treatment.

EXPERIMENTAL DESIGN

Three patient-derived xenograft (PDX) tumors including 2 HER2+ and 1 triple-negative breast cancer harboring DNA damage response (DDR) gene mutations, were implanted subcutaneously in the flank of mice to assess tumor growth inhibition by AZD1390 combined with radiation. Animal survival was further assessed by implanting the best responding PDX model orthotopically in the brain.

RESULTS

Pretreatment with AZD1390 followed by radiation therapy inhibited growth of PDX tumors implanted in the flank, and improved survival in orthotopic models with average survival of 222 days compared with 123 days in controls. Administration of AZD1390 posttreatment for 21 days had no further benefits. While the combination therapy resulted in sustained tumor inhibition, sporadic regrowth was observed in some mice 50 to 100 days posttreatment in all models. Gene expression comparing these tumors with complete responders demonstrated changes in upregulation of oncogenic proteins, which are potential drivers of tumor growth after treatment.

CONCLUSIONS

Our results demonstrate that AZD1390 effectively sensitizes breast cancer CM to radiation therapy in DDR mutant tumors. This study demonstrates the potential of using AZD1390 as a novel therapeutic agent for patients with breast cancer CM.

AKR1C3-dependent lipid droplet formation confers hepatocellular carcinoma cell adaptability to targeted therapy

Rationale: Increased lipid droplet (LD) formation has been linked to tumor metastasis, stemness, and chemoresistance in various types of cancer. Here, we revealed that LD formation is critical for the adaptation to sorafenib in hepatocellular carcinoma (HCC) cells. We aim to investigate the LD function and its regulatory mechanisms in HCC. Methods: The key proteins responsible for LD formation were screened by both metabolomics and proteomics in sorafenib-resistant HCC cells and further validated by immunoblotting and immunofluorescence staining. Biological function of AKR1C3 was evaluated by CRISPR/Cas9-based gene editing. Isotopic tracing analysis with deuterium³-labeled palmitate or carbon13-labeled glucose was conducted to investigate fatty acid (FA) and glucose carbon flux. Seahorse analysis was performed to assess the glycolytic flux and mitochondrial function. Selective AKR1C3 inhibitors were used to evaluate the effect of AKR1C3 inhibition on HCC tumor growth and induction of autophagy. Results: We found that long-term sorafenib treatment impairs fatty acid oxidation (FAO), leading to LD accumulation in HCC cells. Using multi-omics analysis in cultured HCC cells, we identified that aldo-keto reductase AKR1C3 is responsible for LD accumulation in HCC. Genetic loss of AKR1C3 fully depletes LD contents, navigating FA flux to phospholipids, sphingolipids, and mitochondria. Furthermore, we found that AKR1C3-dependent LD accumulation is required for mitigating sorafenib-induced mitochondrial lipotoxicity and dysfunction. Pharmacologic inhibition of AKR1C3 activity instantly induces autophagy-dependent LD catabolism, resulting in mitochondrial fission and apoptosis in sorafenib-resistant HCC clones. Notably, manipulation of AKR1C3 expression is sufficient to drive the metabolic switch between FAO and glycolysis. Conclusions: Our findings revealed that AKR1C3-dependent LD formation is critical for the adaptation to sorafenib in HCC through regulating lipid and energy homeostasis. AKR1C3-dependent LD accumulation protects HCC cells from sorafenib-induced mitochondrial lipotoxicity by regulating lipophagy. Targeting AKR1C3 might be a promising therapeutic strategy for HCC tumors.

Isocitrate dehydrogenase 2 inhibitor enasidenib synergizes daunorubicin cytotoxicity by targeting aldo-keto reductase 1C3 and ATP-binding cassette transporters

Targeting mutations that trigger acute myeloid leukaemia (AML) has emerged as a refined therapeutic approach in recent years. Enasidenib (Idhifa) is the first selective inhibitor of mutated forms of isocitrate dehydrogenase 2 (IDH2) approved against relapsed/refractory AML. In addition to its use as monotherapy, a combination trial of enasidenib with standard intensive induction therapy (daunorubicin + cytarabine) is being evaluated. This study aimed to decipher enasidenib off-target molecular mechanisms involved in anthracycline resistance, such as reduction by carbonyl reducing enzymes (CREs) and drug efflux by ATP-binding cassette (ABC) transporters. We analysed the effect of enasidenib on daunorubicin (Daun) reduction by several recombinant CREs and different human cell lines expressing aldo-keto reductase 1C3 (AKR1C3) exogenously (HCT116) or endogenously (A549 and KG1a). Additionally, A431 cell models overexpressing ABCB1, ABCG2, or ABCC1 were employed to evaluate enasidenib modulation of Daun efflux. Furthermore, the potential synergism of enasidenib over Daun cytotoxicity was quantified amongst all the cell models. Enasidenib selectively inhibited AKR1C3-mediated inactivation of Daun in vitro and in cell lines expressing AKR1C3, as well as its extrusion by ABCB1, ABCG2, and ABCC1 transporters, thus synergizing Daun cytotoxicity to overcome resistance. This work provides in vitro evidence on enasidenib-mediated targeting of the anthracycline resistance actors AKR1C3 and ABC transporters under clinically achievable concentrations. Our findings may encourage its combination with intensive chemotherapy and even suggest that the effectiveness of enasidenib as monotherapy against AML could lie beyond the targeting of mIDH2.

Cytoplasmic fatty acid-binding proteins in metabolic diseases and cancers

Cytoplasmic fatty acid-binding proteins (FABPs) are multipurpose proteins that can modulate lipid fluxes, trafficking, signaling, and metabolism. FABPs regulate metabolic and inflammatory pathways, its inhibition can improve type 2 diabetes mellitus and atherosclerosis. In addition, FABPs are involved in obesity, metabolic disease, cardiac dysfunction, and cancers. FABPs are promising tissue biomarkers in solid tumors for diagnostic and/or prognostic targets for novel therapeutic strategies. The signaling responsive elements of FABPs and determinants of FABP-mediated functions may be exploited in preventing or treating these diseases.

Downregulation of Dihydrotestosterone and Estradiol Levels by HEXIM1

We have previously reported that hexamethylene bis-acetamide inducible protein 1 (HEXIM1) inhibits the activity of ligand-bound estrogen receptor α (ERα) and the androgen receptor (AR) by disrupting the interaction between these receptors and positive transcriptional elongation factor b (P-TEFb) and attenuating RNA polymerase II (RNAPII) phosphorylation at serine 2. Functional consequences of the inhibition of transcriptional activity of ERα and AR by HEXIM1 include the inhibition of ERα- and AR-dependent gene expression, respectively, and the resulting attenuation of breast cancer (BCa) and prostate cancer (PCa) cell proliferation and growth. In our present study, we determined that HEXIM1 inhibited AKR1C3 expression in BCa and PCa cells. AKR1C3, also known as 17β-hydroxysteroid dehydrogenase (17β-HSD) type 5, is a key enzyme involved in the synthesis of 17β-estradiol (E2) and 5-dihydrotestosterone (DHT). Downregulation of AKR1C3 by HEXIM1 influenced E2 and DHT production, estrogen- and androgen-dependent gene expression, and cell proliferation. Our studies indicate that HEXIM1 has the unique ability to inhibit both the transcriptional activity of the ER and AR and the synthesis of the endogenous ligands of these receptors.

Fatty acids and evolving roles of their proteins in neurological, cardiovascular disorders and cancers

The dysregulation of fat metabolism is involved in various disorders, including neurodegenerative, cardiovascular, and cancers. The uptake of long-chain fatty acids (LCFAs) with 14 or more carbons plays a pivotal role in cellular metabolic homeostasis. Therefore, the uptake and metabolism of LCFAs must constantly be in tune with the cellular, metabolic, and structural requirements of cells. Many metabolic diseases are thought to be driven by the abnormal flow of fatty acids either from the dietary origin and/or released from adipose stores. Cellular uptake and intracellular trafficking of fatty acids are facilitated ubiquitously with unique combinations of fatty acid transport proteins and cytoplasmic fatty acid-binding proteins in every tissue. Extensive data are emerging on the defective transporters and metabolism of LCFAs and their clinical implications. Uptake and metabolism of LCFAs are crucial for the brain's functional development and cardiovascular health and maintenance. In addition, data suggest fatty acid metabolic transporter can normalize activated inflammatory response by reprogramming lipid metabolism in cancers. Here we review the current understanding of how LCFAs and their proteins contribute to the pathophysiology of three crucial diseases and the mechanisms involved in the processes.

A new flavonoid derivative exerts antitumor effects against androgen-sensitive to cabazitaxel-resistant prostate cancer cells

BACKGROUND

Our previous report has shown that the flavonoid 2'-hydroxyflavanone (2'-HF) showed inhibition of androgen receptor (AR) activity against androgen-sensitive prostate cancer (PCa) cells, LNCaP, and exhibited antitumor effects against androgen-insensitive PCa cells, PC-3, and DU145. In the present study, we prepared a derivative of 2'-HF, 16MS7F1924, and confirmed the effects of this derivative on PCa cells.

METHODS

The antiproliferation effects of 16MS7F1924 were investigated in PCa cells using LNCaP, PC-3, DU145 and docetaxel-resistant and cabazitaxel-resistant cell lines of PC-3-TxR/CxR and DU145-TxR/CxR. Prostate-specific antigen (PSA) and AR expression level in whole cells and the nucleus were confirmed in LNCaP by reverse transcriptase polymerase chain reaction and Western blot analysis. AR activity in LNCaP cells was confirmed by luciferase assay using PSA promoter-driven reporter. To analyze the antiproliferative effects, cell-based assays using flow cytometry, immunocytochemistry, and TUNEL assay as well as Western blot analysis were employed. Furthermore, PC-3, DU145 and each chemoresistant strain of human PCa cells were subcutaneously xenografted. The antitumor effects of 16MS7F1924 were evaluated in vivo.

RESULTS

16MS7F1924 showed antitumor effect on all PCa cells in a dose-dependent manner. 16MS7F1924 reduced the expression of PSA messenger RNA (mRNA) and protein and inhibited AR activity in a dose-dependent manner, while expression of AR protein and mRNA was reduced by 16MS7F1924. 16MS7F1924 induced mitotic catastrophe and apoptosis. Apoptotic cells were increased in a dose-dependent manner, and the apoptosis was mediated through the Akt pathway. Tumor growth was safely and significantly inhibited by both intraperitoneal and oral administration of 16MS7F1924 in vivo.

CONCLUSION

16MS7F1924 had sufficient antitumor activity against androgen-sensitive and cabazitaxel-resistant PCa cells and may be useful as a novel therapeutic agent overcoming hormone- and chemoresistant PCas.

Mesoporous silica nanoparticles combined with AKR1C3 siRNA inhibited the growth of castration-resistant prostate cancer by suppressing androgen synthesis in vitro and in vivo

Intracrine androgen synthesis plays a critical role in the development of castration-resistant prostate cancer (CRPC). Aldo-keto reductase family 1 member C3 (AKR1C3) is a vital enzyme in the intracrine androgen synthesis pathway. In this study, mesoporous silica nanoparticles (MSNs) were employed to deliver small interfering RNA targeting AKR1C3 (siAKR1C3) to downregulate AKR1C3 expression in CPRC cells. The optimal weight ratio of MSNs/siAKR1C3 was determined by a gel retardation assay. Prostate cancer cells such as VCaP cells, which intracrinally express AKR1C3, and LNCaP-AKR1C3 cells stably transfected with AKR1C3 were used to investigate the antitumour effect of MSNs-siAKR1C3. Fluorescence detection and Western blot analyses were applied to confirm the entrance of MSNs-siAKR1C3 into the cells. A SRB (Sulforhodamine B) assay was employed to assess the cell viability, and a radioimmunoassay was used to measure the androgen concentration. Moreover, real-time PCR (RT-PCR), Western blot analysis and ELISA were used to determine the transcription and expression of prostate-specific antigen (PSA), AKR1C3 and androgen receptor (AR). Meanwhile, a reporter gene assay was performed to determine the AR activity. Additionally, a castrated nude mouse xenograft tumour model was produced to verify the inhibitory effect of MSNs-siAKR1C3 in vivo. The results showed that the optimal weight ratio of MSNs/siAKR1C3 was 140:1, and the complex could effectively enter cells, downregulate AKR1C3 expression, reduce the androgen concentration, inhibit AR activation, and inhibit CRPC development both in vitro and in vivo. These results indicate that decreasing intracrine androgen synthesis and inactivating AR signals by MSNs-siAKR1C3 may be a potential effective method for CRPC treatment.

Bruton's Tyrosine Kinase Inhibitors Ibrutinib and Acalabrutinib Counteract Anthracycline Resistance in Cancer Cells Expressing AKR1C3

Simple Summary

The enzyme aldo-keto reductase 1C3 (AKR1C3) is present in several cancers, in which it is capable of actively metabolising different chemotherapy drugs and decreasing their cytotoxic effects. Therefore, the combination with specific inhibitors of AKR1C3 might prevent drug metabolism and increase its efficacy. We investigated the ability of Bruton’s tyrosine kinase inhibitors ibrutinib and acalabrutinib to block the AKR1C3 mediated inactivation of the anthracycline daunorubicin. Experimentation with recombinant AKR1C3 and different cancer cells expressing this enzyme outlined BTK-inhibitors as potential partners to synergise daunorubicin cytotoxicity in vitro. This evidence could be useful to improve the clinical outcome of anthracycline-based chemotherapies.

Abstract

Over the last few years, aldo-keto reductase family 1 member C3 (AKR1C3) has been associated with the emergence of multidrug resistance (MDR), thereby hindering chemotherapy against cancer. In particular, impaired efficacy of the gold standards of induction therapy in acute myeloid leukaemia (AML) has been correlated with AKR1C3 expression, as this enzyme metabolises several drugs including anthracyclines. Therefore, the development of selective AKR1C3 inhibitors may help to overcome chemoresistance in clinical practice. In this regard, we demonstrated that Bruton’s tyrosine kinase (BTK) inhibitors ibrutinib and acalabrutinib efficiently prevented daunorubicin (Dau) inactivation mediated by AKR1C3 in both its recombinant form as well as during its overexpression in cancer cells. This revealed a synergistic effect of BTK inhibitors on Dau cytotoxicity in cancer cells expressing AKR1C3 both exogenously and endogenously, thus reverting anthracycline resistance in vitro. These findings suggest that BTK inhibitors have a novel off-target action, which can be exploited against leukaemia through combination regimens with standard chemotherapeutics like anthracyclines.

Small Molecule Destabilizer of β-Catenin and Ras Proteins Antagonizes Growth of K-Ras Mutation-Driven Colorectal Cancers Resistant to EGFR Inhibitors

BACKGROUND

Oncogenic K-Ras mutations in colorectal cancer (CRC) combined with APC mutations worsen CRC prognosis and lower drug effectiveness. Thus, inhibition of both Wnt/β-catenin and Ras-MAPK signaling may be a rational strategy to improve the treatment of this cancer.

OBJECTIVE

To identify a novel compound inhibiting both Wnt/β-catenin and Ras-MAPK signaling in CRC.

METHODS AND PATIENTS

We developed a two-part screening system consisting of analysis of TOP flash reporter cells and then potential toxicity effects on primary neural stem cells (NSCs). We then screened 2000 chemical compounds and tested efficacy of candidates against isogenic colon cancer cells harboring wild-type or mutant K-Ras. We employed immunohistochemistry and immunocytochemistry to determine marker signatures associated with development of disease phenotypes.

RESULTS

We identified CPD0857, a compound that inactivates Wnt/β-catenin signaling and promotes ubiquitin-dependent proteasomal degradation of β-catenin and Ras proteins. CPD0857 effectively decreased proliferation and increased apoptosis of CRC cell lines, and overcame resistance of CRC harboring APC and K-Ras mutations to treatment with an EGFR monoclonal antibody (mAb). Moreover, CPD0857 attenuated invasiveness of highly migratory CRC cells in vitro. Accordingly, xenograft mice treated with CPD0857 showed slower tumor growth and significant decreases in both β-catenin and Ras protein expression.

CONCLUSIONS

CPD0857 may be a potential drug for treating aggressive CRC carrying mutations that aberrantly activate Wnt/β-catenin and Ras-ERK pathways.

Selective inhibition of aldo-keto reductase 1C3: a novel mechanism involved in midostaurin and daunorubicin synergism

Midostaurin is an FMS-like tyrosine kinase 3 receptor (FLT3) inhibitor that provides renewed hope for treating acute myeloid leukaemia (AML). The limited efficacy of this compound as a monotherapy contrasts with that of its synergistic combination with standard cytarabine and daunorubicin (Dau), suggesting a therapeutic benefit that is not driven only by FLT3 inhibition. In an AML context, the activity of the enzyme aldo-keto reductase 1C3 (AKR1C3) is a crucial factor in chemotherapy resistance, as it mediates the intracellular transformation of anthracyclines to less active hydroxy metabolites. Here, we report that midostaurin is a potent inhibitor of Dau inactivation mediated by AKR1C3 in both its recombinant form as well as during its overexpression in a transfected cell model. Likewise, in the FLT3^- AML cell line KG1a, midostaurin was able to increase the cellular accumulation of Dau and significantly decrease its metabolism by AKR1C3 simultaneously. The combination of those mechanisms increased the nuclear localization of Dau, thus synergizing its cytotoxic effects on KG1a cells. Our results provide new in vitro evidence of how the therapeutic activity of midostaurin could operate beyond targeting the FLT3 receptor.

Meta-Analysis of steroid-converting enzymes and related receptors in prostate cancer suggesting novel combined therapies

Androgen receptor (AR) signaling is essential for prostate cancer (PC) progression and treatment. Experiments have demonstrated that the intratumoral androgen levels are not affected by circulating androgen levels, but rather modulated by local steroid-converting enzyme activities. The expression modulation status of human steroid-converting enzymes and nuclear receptors are of great promise to identify novel therapeutic targets. Meta-analysis was performed with 9 cohorts (1093 specimens) from Gene Expression Omnibus, 16 cohorts (933 specimens) from Oncomine and the TCGA cohort (550 specimens). We found significant up regulation of 5α-reductase type 1 and type 3 in both primary and metastatic PC, together with the down regulation of AKR1C2 in primary PC, contributing to the high intratumoral DHT levels. The expression of AR in metastatic PC was up regulated, indicating the importance of AR signaling in the progression of this cancer. The down regulations of HSD11B1 and NR3C1 in primary and metastatic PC may diminish the anti-inflammation and anti-proliferation effects of glucocorticoids signaling. Furthermore, the decrease of progesterone receptor (PGR) expression in primary and metastatic PC was also observed, relieving the suppression effect of PGR on PC proliferation. The clinical evidences of the remarkable expression modulation of steroid-converting enzymes and receptors in PC may indicate novel combined treatment against this highly incident cancer.

Enhancing Anti-Tumor Activity of Sorafenib Mesoporous Silica Nanomatrix in Metastatic Breast Tumor and Hepatocellular Carcinoma via the Co-Administration with Flufenamic Acid

Introduction

Because tumor-associated inflammation is a hallmark of cancer treatment, in the present study, sorafenib mesoporous silica nanomatrix (MSNM@SFN) co-administrated with flufenamic acid (FFA, a non-steroidal anti–inflammatory drug (NSAID)) was investigated to enhance the anti-tumor activity of MSNM@SFN.

Methods

Metastatic breast tumor 4T1/luc cells and hepatocellular carcinoma HepG2 cells were selected as cell models. The effects of FFA in vitro on cell migration, PGE2 secretion, and AKR1C1 and AKR1C3 levels in 4T1/luc and HepG2 cells were investigated. The in vivo anti-tumor activity of MSNM@SFN co-administrating with FFA (MSNM@SFN+FFA) was evaluated in a 4T1/luc metastatic tumor model, HepG2 tumor-bearing nude mice model, and HepG2 orthotopic tumor-bearing nude mice model, respectively.

Results

The results indicated that FFA could markedly decrease cell migration, PGE2 secretion, and AKR1C1 and AKR1C3 levels in both 4T1/luc and HepG2 cells. The enhanced anti-tumor activity of MSNM@SFN+FFA compared with that of MSNM@SFN was confirmed in the 4T1/luc metastatic tumor model, HepG2 tumor-bearing nude mice model, and HepG2 orthotopic tumor-bearing nude mice model in vivo, respectively.

Discussion

MSNM@SFN co-administrating with FFA (MSNM@SFN+FFA) developed in this study is an alternative strategy for improving the therapeutic efficacy of MSNM@SFN via co-administration with NSAIDs.

Transition from androgenic to neurosteroidal action of 5α-androstane-3α, 17β-diol through the type A γ-aminobutyric acid receptor in prostate cancer progression

Androgen ablation is the standard of care prescribed to patients with advanced or metastatic prostate cancer (PCa) to slow down disease progression. Unfortunately, a majority of PCa patients under androgen ablation progress to castration-resistant prostate cancer (CRPC). Several mechanisms including alternative intra-prostatic androgen production and androgen-independent androgen receptor (AR) activation have been proposed for CRPC progression. Aldo-keto reductase family 1 member C3 (AKR1C3), a multi-functional steroid metabolizing enzyme, is specifically expressed in the cytoplasm of PCa cells; and positive immunoreactivity of the type A γ-aminobutyric acid receptor (GABA_AR), an ionotropic receptor and ligand-gated ion channel, is detected on the membrane of PCa cells. We studied a total of 72 radical prostatectomy cases by immunohistochemistry, and identified that 21 cases exhibited positive immunoreactivities for both AKR1C3 and GABA_AR. In the dual positive cancer cases, AKR1C3 and GABA_AR subunit α₁ were either expressed in the same cells or in neighboring cells. Among several possible substrates, AKR1C3 reduces 5α-dihydrotesterone (DHT) to form 5α-androstane-3α, 17β-diol (3α-diol). 3α-diol is a neurosteroid that acts as a positive allosteric modulator of the GABA_AR in the central nervous system (CNS). We examined the hypothesis that 3α-diol-regulated pathological effects in the prostate are GABA_AR-dependent, but are independent of the AR. In GABA_AR-positive, AR-negative human PCa PC-3 cells, 3α-diol significantly stimulated cell growth in culture and the in ovo chorioallantoic membrane (CAM) xenograft model. 3α-diol also up-regulated expression of the epidermal growth factor (EGF) family of growth factors and activation of EGF receptor (EGFR) and Src as measured by quantitative polymerase chain reaction and immunoblotting, respectively. Inclusion of GABA_AR antagonists reversed 3α-diol-stimulated tumor cell growth, expression of EGF family members, and activation of EGFR and Src to the level observed in untreated cells. Results from the present study suggest that 3α-diol may act as an alternative intra-prostatic neurosteroid that activates AR-independent PCa progression. The involvement of AKR1C3-mediated steroid metabolisms in modulating GABA_AR activation and promoting PCa progression requires continued studies.

AKR1C enzymes sustain therapy resistance in paediatric T-ALL

Background

Despite chemotherapy intensification, a subgroup of high-risk paediatric T-cell acute lymphoblastic leukemia (T-ALL) patients still experience treatment failure. In this context, we hypothesised that therapy resistance in T-ALL might involve aldo-keto reductase 1C (AKR1C) enzymes as previously reported for solid tumors.

Methods

Expression of NRF2-AKR1C signaling components has been analysed in paediatric T-ALL samples endowed with different treatment outcomes as well as in patient-derived xenografts of T-ALL. The effects of AKR1C enzyme modulation has been investigated in T-ALL cell lines and primary cultures by combining AKR1C inhibition, overexpression, and gene silencing approaches.

Results

We show that T-ALL cells overexpress AKR1C1-3 enzymes in therapy-resistant patients. We report that AKR1C1-3 enzymes play a role in the response to vincristine (VCR) treatment, also ex vivo in patient-derived xenografts. Moreover, we demonstrate that the modulation of AKR1C1-3 levels is sufficient to sensitise T-ALL cells to VCR. Finally, we show that T-ALL chemotherapeutics induce overactivation of AKR1C enzymes independent of therapy resistance, thus establishing a potential resistance loop during T-ALL combination treatment.

Conclusions

Here, we demonstrate that expression and activity of AKR1C enzymes correlate with response to chemotherapeutics in T-ALL, posing AKR1C1-3 as potential targets for combination treatments during T-ALL therapy.

Integrating Multiple Data Sources for Combinatorial Marker Discovery: A Study in Tumorigenesis

Identification of combinatorial markers from multiple data sources is a challenging task in bioinformatics. Here, we propose a novel computational framework for identifying significant combinatorial markers ( s) using both gene expression and methylation data. The gene expression and methylation data are integrated into a single continuous data as well as a (post-discretized) boolean data based on their intrinsic (i.e., inverse) relationship. A novel combined score of methylation and expression data (viz., ) is introduced which is computed on the integrated continuous data for identifying initial non-redundant set of genes. Thereafter, (maximal) frequent closed homogeneous genesets are identified using a well-known biclustering algorithm applied on the integrated boolean data of the determined non-redundant set of genes. A novel sample-based weighted support ( ) is then proposed that is consecutively calculated on the integrated boolean data of the determined non-redundant set of genes in order to identify the non-redundant significant genesets. The top few resulting genesets are identified as potential s. Since our proposed method generates a smaller number of significant non-redundant genesets than those by other popular methods, the method is much faster than the others. Application of the proposed technique on an expression and a methylation data for Uterine tumor or Prostate Carcinoma produces a set of significant combination of markers. We expect that such a combination of markers will produce lower false positives than individual markers.

Simvastatin in combination with meclofenamic acid inhibits the proliferation and migration of human prostate cancer PC-3 cells via an AKR1C3 mechanism

Statins have become of interest in research due to their anticancer effects. However, the exact mechanism of their anticancer properties remains unclear. The authors previously reported that statins decrease intracellular cholesterol levels in androgen-independent prostate cancer cells. In de novo androgen synthesis, cholesterol is the primary material and certain enzymes have important roles. The present study aimed to determine whether simvastatin alters the expression of androgen synthesis-associated enzymes in androgen-independent prostate cancer cells. A novel combination therapy of statins and other drugs that inhibit the overexpression of enzymes involved in androgen synthesis was explored. The cytotoxicity of simvastatin and meclofenamic acid was assessed in prostate cancer cells using MTS and migration assays. Testosterone and dihydrotestosterone concentrations in the culture medium were measured using liquid chromatography-tandem mass spectrometry. RAC-α-serine/threonine-protein kinase (Akt) phosphorylation was detected by western blot analysis. Following treatment with simvastatin, aldo-keto reductase family 1 member C3 (AKR1C3) expression increased in PC-3 (>60-fold) and LNCaP-LA cells, however not in 22Rv1 cells. Small interfering (si)RNA was used to clarify the effects of AKR1C3 expression. The reduction in AKR1C3 expression in PC-3 cells following siRNA transfection was not associated with basal cell proliferation and migration; however, treatment with simvastatin decreased cell proliferation and migration. The combination of simvastatin and meclofenamic acid, an AKR1C3 inhibitor, further enhanced the inhibition of cell proliferation and migration compared with treatment with either drug alone. Furthermore, treatment with simvastatin attenuated insulin-like growth factor 1-induced Akt activation; however, the combination of simvastatin and meclofenamic acid further inhibited Akt activation. These results suggest that the combination of simvastatin and meclofenamic acid may be an effective strategy for the treatment of castration-resistant prostate cancer.

The roles of AKR1C1 and AKR1C2 in ethyl-3,4-dihydroxybenzoate induced esophageal squamous cell carcinoma cell death

The aldo-keto reductase (AKR) superfamily of enzymes is critical for the detoxification of drugs and toxins in the human body; these enzymes are involved not only in the development of drug resistance in cancer cells but also in the metabolism of polycyclic aromatic hydrocarbons. Here, we demonstrated that AKR1C1/C2 increased the metabolism of ethyl-3,4-dihydroxybenzoate (EDHB) in esophageal squamous cell carcinoma (ESCC) cells. Previous studies have shown that EDHB can effectively induce esophageal cancer cell autophagy and apoptosis, and the AKR1C family represents one set of highly expressed genes after EDHB treatment. To explore the cytotoxic effects of EDHB, esophageal cancer cells with higher (KYSE180) or lower (KYSE510) AKR1C expression levels were evaluated in this study. The proliferation of KYSE180 cells was inhibited more effectively than that of KYSE510 cells by EDHB treatment. Furthermore, the effective subunits of the AKR superfamily, AKR1C1/C2, were quantitatively identified using multiple reaction monitoring (MRM) assays. The sensitivity of esophageal cancer cells to EDHB was significantly attenuated by the siRNA knockdown of AKR1C1/C2. Moreover, the expression of autophagy inducers (Beclin, LC3II and BNIP3) and NDRG1 was significantly elevated in KYSE180 cells, but not in KYSE510 cells, after EDHB treatment. When autophagy was inhibited by 3-methyladenine, KYSE180 cells exhibited an increased sensitivity to EDHB, which may be a metabolic substrate of AKR1C1/C2. These results indicated that ESCC patients with high AKR1C1/C2 expression may be more sensitive to EDHB, and AKR1C1/C2 may facilitate EDHB-induced autophagy and apoptosis, thus providing potential guidance for the chemoprevention of ESCC.

Androgen metabolism genes in prostate cancer health disparities

For men in the United States, prostate cancer is common, and newly diagnosed cases of prostate cancer outnumber those of all other cancer types. For prostate cancer, there are racial disparities between Caucasian Americans and African Americans. Androgens and androgen metabolism may be involved in these disparities as well as in the initiation and progression of prostate cancer. Here, we analyzed, in the Cancer Genome Atlas (TCGA) database, the mRNA expression of genes involved in androgen metabolism in prostate cancer based on the patient's race. The results revealed that expressions of UGT2B15 and CYP3A5 are higher but that SRD5A2, CYP17A1, HSD3B2, and AKR1C3 are lower in African American prostate cancers than in those of Caucasian Americans. These genes may relate to the racial disparities associated with prostate cancer. However, the evidence require validation and functional analysis.

Quantitative proteomics and phosphoproteomics on serial tumor biopsies from a sorafenib-treated HCC patient

Compensatory signaling pathways in tumors confer resistance to targeted therapy, but the pathways and their mechanisms of activation remain largely unknown. We describe a procedure for quantitative proteomics and phosphoproteomics on snap-frozen biopsies of hepatocellular carcinoma (HCC) and matched nontumor liver tissue. We applied this procedure to monitor signaling pathways in serial biopsies taken from an HCC patient before and during treatment with the multikinase inhibitor sorafenib. At diagnosis, the patient had an advanced HCC. At the time of the second biopsy, abdominal imaging revealed progressive disease despite sorafenib treatment. Sorafenib was confirmed to inhibit MAPK signaling in the tumor, as measured by reduced ribosomal protein S6 kinase phosphorylation. Hierarchical clustering and enrichment analysis revealed pathways broadly implicated in tumor progression and resistance, such as epithelial-to-mesenchymal transition and cell adhesion pathways. Thus, we describe a protocol for quantitative analysis of oncogenic pathways in HCC biopsies and obtained first insights into the effect of sorafenib in vivo. This protocol will allow elucidation of mechanisms of resistance and enable precision medicine.

Knockdown of AKR1C3 exposes a potential epigenetic susceptibility in prostate cancer cells

BACKGROUND

The aldo-keto reductase 1C3 (AKR1C3) has been heavily implicated in the propagation of prostate malignancy. AKR1C3 protein is elevated within prostate cancer tissue, it contributes to the formation of androgens and downstream stimulation of the androgen receptor (AR). Elevated expression of AKR1C3 is also reported in acute myeloid leukemia but the target nuclear receptors have been identified as members of the peroxisome-proliferator activated receptor (PPARs) subfamily. Thus, AKR1C3 cancer biology is likely to be tissue dependent and hormonally linked to the availability of ligands for both the steroidogenic and non-steroidogenic nuclear receptors.

METHODS

In the current study we investigated the potential for AKR1C3 to regulate the availability of prostaglandin-derived ligands for PPARg mainly, prostaglandin J2 (PGJ2). Using prostate cancer cell lines with stably reduced AKR1C3 levels we examined the impact of AKR1C3 upon proliferation mediated by PPAR ligands.

RESULTS

These studies revealed knockdown of AKR1C3 had no effect upon the sensitivity of androgen receptor independent prostate cancer cells towards PPAR ligands. However, the reduction of levels of AKR1C3 was accompanied by a significantly reduced mRNA expression of a range of HDACs, transcriptional co-regulators, and increased sensitivity towards SAHA, a clinically approved histone deacetylase inhibitor.

CONCLUSIONS

These results suggest a hitherto unidentified link between AKR1C3 levels and the epigenetic status in prostate cancer cells. This raises an interesting possibility of a novel rational to target AKR1C3, the utilization of AKRIC3 selective inhibitors in combination with HDAC inhibition as part of novel epigenetic therapies in androgen deprivation therapy recurrent prostate cancer.

Transcript level of AKR1C3 is down-regulated in gastric cancer

Steroid hormones have been shown to play a role in gastric carcinogenesis. Large amounts of steroid hormones are locally produced in the peripheral tissues of both genders. Type 5 of 17β-hydroxysteroid dehydrogenase, encoded by the AKR1C3 gene, plays a pivotal role in both androgen and estrogen metabolism, and its expression was found to be deregulated in different cancers. In this study we measured AKR1C3 transcript and protein levels in nontumoral and primary tumoral gastric tissues, and evaluated their association with some clinicopathological features of gastric cancer (GC). We found decreased levels of AKR1C3 transcript (p < 0.0001) and protein (p = 0.0021) in GC tissues compared with the adjacent, apparently histopathologically normal, mucosa. Lower levels of AKR1C3 transcript were observed in diffuse and intestinal types of GC, whereas AKR1C3 protein levels were decreased in tumors with multisite localization, in diffuse histological type, T3, T4, and G3 grades. We also determined the effect of the histone deacetylase inhibitor sodium butyrate (NaBu) on AKR1C3 expression in EPG 85-257 and HGC-27 GC cell lines. We found that NaBu elevates the levels of both AKR1C3 transcript and protein in the cell lines we investigated. Together, our results suggest that decreased expression of AKR1C3 may be involved in development of GC and can be restored by NaBu.

11β-Prostaglandin F2α, a bioactive metabolite catalyzed by AKR1C3, stimulates prostaglandin F receptor and induces slug expression in breast cancer

Prostaglandins are a group of lipid compounds involved in inflammation and cancer. We focused on PGF2α and its stereoisomer 11β-PGF2α and examined the expression and functions of their cognate receptor (FP receptor) and metabolizing enzymes (AKR1B1 and AKR1C3 respectively) in breast cancer. In immunohistochemical analysis FP receptor status associated with adverse clinical outcome only in the AKR1C3 positive cases. Therefore, we studied FP receptor-mediated functions of 11β-PGF2α using FP receptor expressed MCF-7 cell line (MCF-FP). 11β-PGF2α treatment phosphorylated ERK and CREB and induced Slug expression through FP receptor in MCF-FP, and MCF-FP cells demonstrated decreased chemosensitivity compared to parental controls. Finally, the correlation between FP receptor and Slug was also confirmed immunohistochemically in breast cancer cases. Overall these results indicated that the actions of AKR1C3 can produce FP receptor ligands whose activation results in carcinoma cell survival in breast cancer.

Potential biomarkers associated with diabetic glomerulopathy through proteomics

Diabetic nephropathy (DN) is characterized by the development of progressive glomerulosclerotic lesions gradually leading to an increasing loss of functioning kidney parenchyma. Relatively little proteomic research of isolated glomeruli of experimental animal models has been done so far. Isolated glomerular proteomics is an innovative tool that potentially detects simultaneous expressions of glomeruli in diabetic pathological contexts. We compared the isolated glomerular profiles of rats with and without diabetes. The proteins in the aliquots of glomeruli were subjected to two-dimensional gel electrophoresis. The protein spots were matched and quantified using an imaging analysis system. The peptide mass fingerprints were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry and a bioinformation search. We found that diabetes increased collagen type I and collagen type IV levels in diabetic glomeruli when compared to normal control group using Dynabeads. We found that rats with diabetes had significantly higher abundance of the Protein disulfide isomerase associated 3, Aspartoacylase-3,3-hydroxymethyl-3-methylglutaryl-Coenzyme A lyase, Lactamase beta 2 and Agmat protein. However, diabetic glomeruli in rats had significantly lower levels of the Regucalcin, rCG52140, Aldo-keto reductase family 1, Peroxiredoxin 1, and l-arginine: glycine amidinotransferase. These proteins of interest were reported to modulate disturbances in the homeostasis of endoplasmic reticulum stress, disturbance of inflammatory and fibrinogenic activities, impairing endothelial function, and dysregulation in the antioxidation capacity/oxidative stress in several tissue types under pathological contexts. Taken together, our high-throughput isolated glomerular proteomic findings indicated that multiple pathological reactions presumably occurred in DN.

Elevated expression of AKR1C3 increases resistance of cancer cells to ionizing radiation via modulation of oxidative stress

With the aim to elucidate the etiology of radioresistance, we explored the genetic alterations in non-radioresistant vs. resistant esophageal cancer cells acquired by long-term fractionated radiation. We found AKR1C3, an aldo-keto reductase expressed seldom in most human tissues, expressed higher in radioresistance-acquired cells. Suppression of AKR1C3 via RNAi or its chemical inhibitors restored the sensitivity of the acquired tumor cells and xenograft BALB/c nude mice to ionizing radiation (IR). Cellular monitoring of the oxidative stress in the AKR1C3-elevated cells indicated that IR-induced ROS accumulation and the concomitant DNA damage was significantly alleviated, and such protective consequence disappeared upon AKR1C3 knockdown. These findings uncover the potential involvement of AKR1C3 in removal of cellular ROS and explain, at least partially, the acquired radioresistance by AKR1C3 overexpression. A retrospective analysis of esophageal carcinomas also indicated a significant expression of AKR1C3 in radio-resistant but not radio-sensitive surgical samples. Our study may provide a potential biomarker for predicting prognosis of radiotherapy and even direct a targeted therapy for esophageal cancer and other tumors.

Aldo-keto reductase 1C3 is overexpressed in skin squamous cell carcinoma (SCC) and affects SCC growth via prostaglandin metabolism

Aldo-keto reductase 1C3 (AKR1C3) is an enzyme involved in metabolizing prostaglandins (PGs) and sex hormones. It metabolizes PGD2 to 9α11β-PGF2 , diverting the spontaneous conversion of PGD2 to the PPARγ agonist, 15-Deoxy-Delta-12, 14-prostaglandin J2 (15d-PGJ2 ). AKR1C3 is overexpressed in various malignancies, suggesting a tumor promoting function. This work investigates AKR1C3 expression in human non-melanoma skin cancers, revealing overexpression in squamous cell carcinoma (SCC). Effects of AKR1C3 overexpression were then evaluated using three SCC cell lines. AKR1C3 was detected in all SCC cell lines and its expression was upregulated in response to its substrate, PGD2 . Although attenuating AKR1C3 expression in SCC cells by siRNA did not affect growth, treatment with PGD2 and its dehydration metabolite, 15d-PGJ2 , decreased SCC proliferation in a PPARγ-dependent manner. In addition, treatment with the PPARγ agonist pioglitazone profoundly inhibited SCC proliferation. Finally, we generated an SCC cell line that stably overexpressed AKR1C3 (SCC-AKR1C3). SCC-AKR1C3 metabolized PGD2 to 9α11β-PGF2 12-fold faster than the parent cell line and was protected from the antiproliferative effect mediated by PGD2 . This work suggests that PGD2 and its metabolite 15d-PGJ2 attenuate SCC proliferation in a PPARγ-dependent manner, therefore activation of PPARγ by agonists such as pioglitazone may benefit those at high risk of SCC.

The Activity of SN33638, an Inhibitor of AKR1C3, on Testosterone and 17β-Estradiol Production and Function in Castration-Resistant Prostate Cancer and ER-Positive Breast Cancer

AKR1C3 is a novel therapeutic target in castration-resistant prostate cancer (CRPC) and estrogen receptor (ER)-positive breast cancer because of its ability to produce testosterone and 17β-estradiol intratumorally, thus promoting nuclear receptor signaling and tumor progression. A panel of CRPC, ER-positive breast cancer and high/low AKR1C3-expressing cell lines were treated with SN33638, a selective inhibitor of AKR1C3, in the presence of hormone or prostaglandin (PG) precursors, prior to evaluation of cell proliferation and levels of 11β-PG F2α (11β-PGF2α), testosterone, 17β-estradiol, and prostate-specific antigen (PSA). A meta-analysis of AKR1C3 mRNA expression in patient samples was also conducted, which revealed that AKR1C3 mRNA was upregulated in CRPC, but downregulated in ER-positive breast cancer. 11β-PGF2α and testosterone levels in the cell line panel correlated with AKR1C3 protein expression. SN33638 prevented 11β-PGF2α formation in cell lines that expressed AKR1C3, but partially inhibited testosterone formation and subsequently cell proliferation and/or PSA expression only in high (LAPC4 AKR1C3-overexpressing cells) or moderate (22RV1) AKR1C3-expressing cell lines. SN33638 had little effect on 17β-estradiol production or estrone-stimulated cell proliferation in ER-positive breast cancer cell lines. Although SN33638 could prevent 11β-PGF2α formation, its ability to prevent testosterone and 17β-estradiol production and their roles in CRPC and ER-positive breast cancer progression was limited due to AKR1C3-independent steroid hormone production, except in LAPC4 AKR1C3 cells where the majority of testosterone was AKR1C3-dependent. These results suggest that inhibition of AKR1C3 is unlikely to produce therapeutic benefit in CRPC and ER-positive breast cancer patients, except possibly in the small subpopulation of CRPC patients with tumors that have upregulated AKR1C3 expression and are dependent on AKR1C3 to produce the testosterone required for their growth.

Expression of AKR1C3 and CNN3 as markers for detection of lymph node metastases in colorectal cancer

The aim of the study was to identify a set of discriminating genes that could be used for the prediction of Lymph node (LN) metastasis in human colorectal cancer (CRC), and for this, we compared the whole genome profiles of two CRC cell lines (the primary cell line SW480 and its LN metastatic variant, SW620) and identified eight genes [S100 calcium-binding protein P; aldo–keto reductase family 1(AKR1), member B1 (aldose reductase; AKR1B1); AKR1, member C3 (AKR1C3); calponin 3, acidic; metastasis associated in colon cancer 1; hemoglobin, epsilon 1; trefoil factor 3; and FGGY carbohydrate kinase domain containing]. These genes were examined by quantitative RT-PCR in tissues and LNs in 14 CRC patients and 11 control patients. The level of AKR1C3 mRNA expression was significantly different between the Dukes’ stage A, B, and C groups and the control group (p < 0.05, p < 0.001, and p < 0.001) and was also significantly different between Dukes’ stage C and A or B groups (p < 0.05 and p < 0.001, respectively). The expression of CNN3 was significantly different between the Dukes’ stage C and B or control groups (p < 0.001 and p < 0.01, respectively). There were significant correlations between the expression levels of AKR1C3 and CNN3. AKR1C3 and CNN3 expressions are more accurate and suitable markers for the diagnosis of LN metastasis than the other six genes examined in this study.

Activation of the PI3K/AKT pathway correlates with prognosis in stage II colon cancer

Background:

Patients with UICC/AJCC stage II colon cancer have a high 5-year overall survival rate after surgery. Nevertheless, a significant subgroup of patients develops tumour recurrence. Currently, there are no clinically established biomarkers available to identify this patient group. We applied reverse-phase protein arrays (RPPA) for phosphatidylinositide-3-kinase pathway activation mapping to stratify patients according to their risk of tumour recurrence after surgery.

Methods:

Full-length proteins were extracted from formalin-fixed, paraffin-embedded tissue samples of 118 patients who underwent curative resection. RPPA technology was used to analyse expression and/or phosphorylation levels of six major factors of the phosphatidylinositide-3-kinase pathway. Oncogenic mutations of KRAS and BRAF, and DNA microsatellite status, currently discussed as prognostic markers, were analysed in parallel.

Results:

Expression of phospho-AKT (HR=3.52; P=0.032), S6RP (HR=6.3; P=0.044), and phospho-4E-BP1 (HR=4.12; P=0.011) were prognostic factors for disease-free survival. None of the molecular genetic alterations were significantly associated with prognosis.

Conclusions:

Our data indicate that activation of the PI3K/AKT pathway evidenced on the protein level might be a valuable prognostic marker to stratify patients for their risk of tumour recurrence. Beside adjuvant chemotherapy targeting of upregulated PI3K/AKT signalling may be an attractive strategy for treatment of high-risk patients.

AKR1C3 overexpression may serve as a promising biomarker for prostate cancer progression

Background

Aldo-keto reductase family 1 member C3 (AKR1C3) is a key steroidogenic enzyme that is overexpressed in prostate cancer (PCa) and is associated with the development of castration-resistant prostate cancer (CRPC). The aim of this study was to investigate the correlation between the expression level of AKR1C3 and the progression of PCa.

Methods

Sixty human prostate needle biopsy tissue specimens and ten LNCaP xenografts from intact or castrated male mice were included in the study. The relationship between the level of AKR1C3 expression by immunohistochemistry and evaluation factors for PCa progression, including prostate-specific antigen (PSA), Gleason score (GS) and age, were analyzed.

Results

Low immunoreactivity of AKR1C3 was detected in normal prostate epithelium, benign prostatic hyperplasia (BPH) and prostatic intraepithelial neoplasia (PIN). Positive staining was gradually increased with an elevated GS in PCa epithelium and LNCaP xenografts in mice after castration. The Spearman’s r values (r_s) of AKR1C3 to GS and PSA levels were 0.396 (P = 0.025) and -0.377 (P = 0.036), respectively, in PCa biopsies. The r_s of AKR1C3 to age was 0.76 (P = 0.011). No statistically significant difference was found with other variables.

Conclusion

Our study suggests that the level of AKR.

1C3 expression is positively correlated with an elevated GS, indicating that AKR1C3 can serve as a promising biomarker for the progression of PCa.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7748245591110149.

Clinical implications of aldo-keto reductase family 1 member C3 and its relationship with lipocalin 2 in cancer of the uterine cervix

OBJECTIVE

Over-expression of the aldo-keto reductase family 1 member C3 (AKR1C3) has been demonstrated in many human cancers. Lipocalin 2 (LCN2) is reported to inhibit cervical cancer metastasis but little is known regarding its relationship with AKR1C3 in the development and progression of uterine cervical cancer. This study aimed to investigate the involvement of AKR1C3 and its relationship with LCN2 in cervical cancer.

METHODS

The roles of AKR1C3 and LCN2 were investigated using the lentivirus shRNA system in SiHa and Caski cervical cancer cells. LCN2 and matrix metalloproteinase-2 (MMP-2) promoters were constructed to demonstrate transcriptional regulation by shAKR1C3 and shLCN2, respectively. The influences of metastatic phenotypes were analyzed by wound healing, Boyden chamber, and immunofluorescence assays. The activity of MMP-2 was determined by zymography assay. The impacts of AKR1C3 and LCN2 on patient prognosis were evaluated using tissue microarrays by Cox regression and Kaplan-Meier models.

RESULTS

Silencing of the AKR1C3 gene increased the expression of LCN2 and decreased the migratory and invasive abilities and changed the cytoskeleton of cervical cancer cells. When AKR1C3 was over-expressed, it decreased LCN2 promoter activity and LCN2 expression and increased cell migration. The mRNA level and enzyme activity of MMP-2 increased in silenced LCN2 cells. Positive AKR1C3 and negative LCN2 were correlated with higher recurrence and poorer survival of cervical cancer patients.

CONCLUSIONS

Silencing of AKR1C3 increases LCN2 expression and inhibits metastasis in cervical cancer. Both AKR1C3 and LCN2 serve as molecular targets for cancer therapy to improve the clinical outcome of cervical cancer patients.

Cancer stem cell-related marker expression in lung adenocarcinoma and relevance of histologic subtypes based on IASLC/ATS/ERS classification

Background

The cancer stem cell (CSC) theory has been proposed to explain tumor heterogeneity and the carcinogenesis of solid tumors. The aim of this study was to clarify the clinical role of CSC-related markers in patients with lung adenocarcinoma and to determine whether each CSC-related marker expression correlates with the histologic subtyping proposed by the International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS), and the European Respiratory Society (ERS) classifications.

Methods

We reviewed data for all 103 patients in whom complete resection of adenocarcinoma had been performed. Expression of CSC-related markers, ie, aldehyde dehydrogenase 1A1 (ALDH1A1), aldo-keto reductase 1C family member 1 (AK1C1), and 1C family member 3 (AK1C3), was examined using immunostaining on whole-mount tissue slides, and the tumors were reclassified according to the IASLC/ATS/ERS classification.

Results

ALDH1A1 expression was observed in 66.0% of tumors, AK1C1 in 62.7%, and AK1C3 in 86.1%. Immunoreactivities with the frequency of mean expression of ALDH1A1 in papillary predominant adenocarcinoma were significantly higher than those of solid predominant adenocarcinoma (P<0.05). Papillary predominant adenocarcinoma had significantly lower expression of AK1C1 when compared with noninvasive or solid predominant adenocarcinomas (P<0.05). On multivariate analysis, larger tumor size (hazards ratio 1.899, P=0.044), lymph node metastasis (hazards ratio 2.702, P=0.005), and low expression of ALDH1A1 (hazards ratio 3.218, P<0.001) were shown to be independently associated with an unfavorable prognosis.

Conclusion

Immunohistochemistry of ALDH1A1 expression is strongly associated with prognosis. Expression of each CSC-related marker varies according to subtype, suggesting that a comprehensive histologic subtyping approach in the IASLC/ATS/ERS classification provides new molecular biology insights into the genesis of lung adenocarcinoma according to CSC theory.

AKR1C3 as a target in castrate resistant prostate cancer

Aberrant androgen receptor (AR) activation is the major driver of castrate resistant prostate cancer (CRPC). CRPC is ultimately fatal and more therapeutic agents are needed to treat this disease. Compounds that target the androgen axis by inhibiting androgen biosynthesis and or AR signaling are potential candidates for use in CRPC treatment and are currently being pursued aggressively. Aldo-keto reductase 1C3 (AKR1C3) plays a pivotal role in androgen biosynthesis within the prostate. It catalyzes the 17-ketoreduction of weak androgen precursors to give testosterone and 5α-dihydrotestosterone. AKR1C3 expression and activity has been implicated in the development of CRPC, making it a rational target. Selective inhibition of AKR1C3 will be important, however, due to the presence of closely related isoforms, AKR1C1 and AKR1C2 that are also involved in androgen inactivation. We examine the evidence that supports the vital role of AKR1C3 in CRPC and recent developments in the discovery of potent and selective AKR1C3 inhibitors. This article is part of a Special Issue entitled 'CSR 2013'.

N-Benzoyl anthranilic acid derivatives as selective inhibitors of aldo-keto reductase AKR1C3

Human aldo-keto reductases AKR1C1-AKR1C3 are involved in the biosynthesis and inactivation of steroid hormones and prostaglandins and thus represent attractive targets for the development of new drugs. We synthesized a series of N-benzoyl anthranilic acid derivatives and tested their inhibitory activity on AKR1C enzymes. Our data show that these derivatives inhibit AKR1C1-AKR1C3 isoforms with low micromolar potency. In addition, five selective inhibitors of AKR1C3 were identified. The most promising inhibitors were compounds 10 and 13, with IC(50) values of 0.31 μM and 0.35 μM for AKR1C3, respectively.

Selective inhibition of human type-5 17β-hydroxysteroid dehydrogenase (AKR1C3) by baccharin, a component of Brazilian propolis

The human aldo-keto reductase (AKR) 1C3, also known as type-5 17β-hydroxysteroid dehydrogenase and prostaglandin F synthase, has been suggested as a therapeutic target in the treatment of prostate and breast cancers. In this study, AKR1C3 inhibition was examined by Brazilian propolis-derived cinnamic acid derivatives that show potential antitumor activity, and it was found that baccharin (1) is a potent competitive inhibitor (K(i) 56 nM) with high selectivity, showing no significant inhibition toward other AKR1C isoforms (AKR1C1, AKR1C2, and AKR1C4). Molecular docking and site-directed mutagenesis studies suggested that the nonconserved residues Ser118, Met120, and Phe311 in AKR1C3 are important for determining the inhibitory potency and selectivity of 1. The AKR1C3-mediated metabolism of 17-ketosteroid and farnesal in cancer cells was inhibited by 1, which was effective from 0.2 μM with an IC(50) value of about 30 μM. Additionally, 1 suppressed the proliferation of PC3 prostatic cancer cells stimulated by AKR1C3 overexpression. This study is the first demonstration that 1 is a highly selective inhibitor of AKR1C3.

Microarray analysis revealed dysregulation of multiple genes associated with chemoresistance to As(2)O(3) and increased tumor aggressiveness in a newly established arsenic-resistant ovarian cancer cell line, OVCAR-3/AsR

The potential of arsenic trioxide (As(2)O(3)) for use as a novel therapy for ovarian cancer treatment has been increasingly recognized. In this study, we developed an arsenic-resistant OVCAR-3 subline (OVCAR-3/AsR) and aimed to identify the molecular mechanisms and signaling pathways contributing to the development of acquired arsenic chemoresistance in ovarian cancer. OVCAR-3/AsR cells were obtained following continual exposure of parental OVCAR-3 cells to low dose As(2)O(3) for 12months. Cytotoxicity of OVCAR-3/AsR cells to As(2)O(3), paclitaxel and cisplatin was investigated. Cell apoptosis and cell cycle distribution following As(2)O(3) treatment of OVCAR-3/AsR cells was also analyzed using flow cytometry. Subsequently, cDNA microarray analysis was performed from the RNA samples of OVCAR-3 and OVCAR-3/AsR cells in duplicate experiments. Microarray data were analyzed using Genespring® and Pathway Studio® Softwares. OVCAR-3/AsR cells showed 9-fold greater resistance to As(2)O(3) and lack of collateral resistance to cisplatin and paclitaxel. Compared with parental OVCAR-3 cells, OVCAR-3/AsR had significantly lower apoptotic rates following As(2)O(3) treatment. These cells were also arrested at both the S phase and G(2)/M phase of the cell cycle after exposure to high concentrations of As(2)O(3). Gene expression profiling revealed significant differences in expression levels of 397 genes between OVCAR-3/AsR and OVCAR-3 cells. The differentially regulated transcripts genes have functional ontologies related to continued cancer cell growth, cell survival, tumor metastasis and tumor aggressiveness. Additionally, numerous gene targets of the nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor showed elevated expression in OVCAR-3/AsR cells. Subsequent pathway analysis further revealed a gene network involving interleukin 1-alpha (IL1A) in mediating the arsenic-resistant phenotype. These results showed that changes in multiple genes and an increased in tumor aggressiveness occurred during the development of acquired chemoresistance to As(2)O(3) in ovarian cancer cells. The functional relevance of these genetic changes should be validated in future studies.

Human aldo-keto reductases: structure, substrate specificity and roles in tumorigenesis

The aldo-keto reductase (AKR) superfamily consists of over 150 protein members sharing similar structure and enzymatic activities. To date, 13 human AKRs have been identified, and they participate in xenobiotic detoxification, biosynthesis and metabolism. Increasing evidence suggests the involvement of human AKR proteins in cancer development, progression and treatment. Some proteins demonstrate multiple functional features in addition to being a reductase for carbonyl groups. This review article discusses the most recent progress made in the study of humans AKRs.