Aldo-keto reductases are biomarkers of NRF2 activity and are co-ordinately overexpressed in non-small cell lung cancer

BACKGROUND: Although the nuclear factor-erythroid 2-related factor 2 (NRF2) pathway is one of the most frequently dysregulated in cancer, it is not clear whether mutational status is a good predictor of NRF2 activity. Here we utilise four members of the aldo-keto reductase (AKR) superfamily as biomarkers to address this question. METHODS: Twenty-three cell lines of diverse origin and NRF2-pathway mutational status were used to determine the relationship between AKR expression and NRF2 activity. AKR expression was evaluated in lung cancer biopsies and Cancer Genome Atlas (TCGA) and Oncomine data sets. RESULTS: AKRs were expressed at a high basal level in cell lines carrying mutations in the NRF2 pathway. In non-mutant cell lines, co-ordinate induction of AKRs was consistently observed following activation of NRF2. Immunohistochemical analysis of lung tumour biopsies and interrogation of TCGA data revealed that AKRs are enriched in both squamous cell carcinomas (SCCs) and adenocarcinomas that contain somatic alterations in the NRF2 pathway but, in the case of SCC, AKRs were also enriched in most other tumours. CONCLUSIONS: An AKR biomarker panel can be used to determine NRF2 status in tumours. Hyperactivation of the NRF2 pathway is far more prevalent in lung SCC than previously predicted by genomic analyses

AKR1C enzymes sustain therapy resistance in paediatric T-ALL

BACKGROUND: Despite chemotherapy intensification, a subgroup of high-risk paediatric T-cell acute lymphoblastic leukemia (TALL) 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

Environmental sensing and response genes in cnidaria : the chemical defensome in the sea anemone Nematostella vectensis

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Cell Biology and Toxicology 24 (2008): 483-502, doi:10.1007/s10565-008-9107-5.The starlet sea anemone Nematostella vectensis has been recently established as a new model system for the study of the evolution of developmental processes, as cnidaria occupy a key evolutionary position at the base of the bilateria. Cnidaria play important roles in estuarine and reef communities, but are exposed to many environmental stressors. Here I describe the genetic components of a ‘chemical defensome’ in the genome of N. vectensis, and review cnidarian molecular toxicology. Gene families that defend against chemical stressors and the transcription factors that regulate these genes have been termed a ‘chemical defensome,’ and include the cytochromes P450 and other oxidases, various conjugating enyzymes, the ATP-dependent efflux transporters, oxidative detoxification proteins, as well as various transcription factors. These genes account for about 1% (266/27200) of the predicted genes in the sea anemone genome, similar to the proportion observed in tunicates and humans, but lower than that observed in sea urchins. While there are comparable numbers of stress-response genes, the stress sensor genes appear to be reduced in N. vectensis relative to many model protostomes and deuterostomes. Cnidarian toxicology is understudied, especially given the important ecological roles of many cnidarian species. New genomic resources should stimulate the study of chemical stress sensing and response mechanisms in cnidaria, and allow us to further illuminate the evolution of chemical defense gene networks.WHOI Ocean Life Institute and NIH R01-ES01591

Role of human aldo -keto reductases in PAH activation

Polycyclic aromatic hydrocarbons are widespread environmental carcinogens implicated in the causation of human lung cancer. PAH require metabolic activation by epoxide hydrolase (EH) and CYPIA1 to form non-K-region trans-dihydrodiols that can be further activated by CYP1A1 to form diol-epoxides. Previously we have shown that a cytosolic aldo-keto reductase (AYR) from rat liver 3α-HSD/DD (AKR1C9) can divert these traps-dihydrodiols to yield reactive and redox active o-quinones, raising the possibility that this pathway could contribute to PAH carcinogenesis. However, whether this pathway occurs in humans was unknown. In this study we determined whether this pathway can be catalyzed in vitro by human AKR1C isoforms. Furthermore, we investigated whether the isoforms are highly over-expressed in lung cells, and whether the activity is sufficient to generate PAH o-quinones. We now demonstrate that four homogenous recombinant human AKRs (AKR1C1-AKR1C4) oxidized a wide variety of PAH trans-dihydrodiols with regio-selectivity. Of the PAH trans-dihydrodiols tested DMBA-3,4-diol, one of the most potent proximate carcinogens known, was often preferred. Using DMBA-3,4-diol the product of the reaction was shown to be DMBA-3,4-dione which was trapped as a thioether conjugate with 2-mercaptoethanol. DMBA-3,4-dione was shown to form mono- and bis-thioether conjugates via a novel mechanism of sequential 1,6- and 1,4-Michael addition. Using multiple tissue expression array analysis, AKR1C isoforms were shown to be highly expressed in several PAH exposed tissues and in the human lung carcinoma cell line A549. Isoform specific RT-PCR identified AKR1C1-AKR1C3 transcripts in this cell line. Western blot analysis and functional assays showed the presence of active AKR1C isoforms in A549 cells. A549 cell lysates were shown to oxidize DMBA-3,4-diol to DMBA-3,4-dione. The ability to measure DMBA-3,4-dione formation in human cells implicates AKR1C isoforms in the metabolic activation of potent proximate carcinogens in lung cancer. DMBA-3,4-dione is the most electrophilic o-quinone produced by AKRs and its unique ability to form bis-thioether conjugates suggests that bis-conjugates may form with other cellular nucleophiles with toxicological consequences. The constitutively and widely expressed AKR, aldehyde reductase (AKR1A1) was also shown to oxidize PAH trans-dihydrodiols to their corresponding o-quinones. Aldehyde reductase displayed regio- and stereoselectivity in oxidizing PAH trans dihydrodiols of varying ring number and arrangement. Aldehyde reductase preferentially oxidized the metabolically relevant (−)-R,R isomer of BP-7,8-diol to yield BP-7,8-dione implicating the importance of this enzyme in PAH activation in humans. Moreover, AKR1A1 was shown to be co-expressed with EH and CYP1A1. The ability of these human AKR enzymes to divert trans-dihydrodiols to o-quinones suggests that this pathway occurs in site of PAH carcinogenesis in humans

Role of human aldo -keto reductases in PAH activation

Polycyclic aromatic hydrocarbons are widespread environmental carcinogens implicated in the causation of human lung cancer. PAH require metabolic activation by epoxide hydrolase (EH) and CYPIA1 to form non-K-region trans-dihydrodiols that can be further activated by CYP1A1 to form diol-epoxides. Previously we have shown that a cytosolic aldo-keto reductase (AYR) from rat liver 3α-HSD/DD (AKR1C9) can divert these traps-dihydrodiols to yield reactive and redox active o-quinones, raising the possibility that this pathway could contribute to PAH carcinogenesis. However, whether this pathway occurs in humans was unknown. In this study we determined whether this pathway can be catalyzed in vitro by human AKR1C isoforms. Furthermore, we investigated whether the isoforms are highly over-expressed in lung cells, and whether the activity is sufficient to generate PAH o-quinones. We now demonstrate that four homogenous recombinant human AKRs (AKR1C1-AKR1C4) oxidized a wide variety of PAH trans-dihydrodiols with regio-selectivity. Of the PAH trans-dihydrodiols tested DMBA-3,4-diol, one of the most potent proximate carcinogens known, was often preferred. Using DMBA-3,4-diol the product of the reaction was shown to be DMBA-3,4-dione which was trapped as a thioether conjugate with 2-mercaptoethanol. DMBA-3,4-dione was shown to form mono- and bis-thioether conjugates via a novel mechanism of sequential 1,6- and 1,4-Michael addition. Using multiple tissue expression array analysis, AKR1C isoforms were shown to be highly expressed in several PAH exposed tissues and in the human lung carcinoma cell line A549. Isoform specific RT-PCR identified AKR1C1-AKR1C3 transcripts in this cell line. Western blot analysis and functional assays showed the presence of active AKR1C isoforms in A549 cells. A549 cell lysates were shown to oxidize DMBA-3,4-diol to DMBA-3,4-dione. The ability to measure DMBA-3,4-dione formation in human cells implicates AKR1C isoforms in the metabolic activation of potent proximate carcinogens in lung cancer. DMBA-3,4-dione is the most electrophilic o-quinone produced by AKRs and its unique ability to form bis-thioether conjugates suggests that bis-conjugates may form with other cellular nucleophiles with toxicological consequences. The constitutively and widely expressed AKR, aldehyde reductase (AKR1A1) was also shown to oxidize PAH trans-dihydrodiols to their corresponding o-quinones. Aldehyde reductase displayed regio- and stereoselectivity in oxidizing PAH trans dihydrodiols of varying ring number and arrangement. Aldehyde reductase preferentially oxidized the metabolically relevant (−)-R,R isomer of BP-7,8-diol to yield BP-7,8-dione implicating the importance of this enzyme in PAH activation in humans. Moreover, AKR1A1 was shown to be co-expressed with EH and CYP1A1. The ability of these human AKR enzymes to divert trans-dihydrodiols to o-quinones suggests that this pathway occurs in site of PAH carcinogenesis in humans

Internet gaming experience among adolescents in Metro Manila: A case study

This study explored the experience of internet gaming disorder (IGD) among adolescents in a high school in Metro Manila. It aimed to understand the antecedents, symptoms and consequences of IGD. The respondents of the study consisted of 8 adolescents with IGD and 8 highly engaged adolescent gamers. This paper used multiple case study research design. Responses from the participants revealed four major themes namely: a) experience of internet gaming, b) risk factors in developing IGD, c) warning signs of IGD, and d) ramifications of IGD. IGD experience includes cognitive, affective, physiological and behavioral reactions. Risk factors in developing IGD involve excessive gaming, escapism and coping, entertainment and peer recognition. Pre-occupation with gaming, inability to control the urge to play and lie/deception about gaming are warning signs of IGD while having relational conflicts caused by gaming and declining of grades are ramifications of IGD. Parental control over gaming serves as protective factors for the highly engaged gamers. Implications for counseling practice are discussed. Keywords: internet gaming disorder, internet gaming, counseling, Filipino adolescent

Influences and processes of counseling orientation development: Its implication to future practice

Many Filipino counselors do not directly claim a specific counseling orientation. A lot of them emphasize micro-skills in helping or random use of various counseling approaches. The present study interviewed eight registered counselors with more than ten years of counseling experience and with doctorate degrees in counseling. The present study aimed to establish a model of the influences and processes that are involved in counseling orientation development. It employed content analysis, with audio-taped in-depth interview as the primary source of data collection. Results showed an interaction between1) personal and 2) professional processes. These two major domains with four factors each influence counselors in developing a workable counseling orientation. Implications for personal satisfaction and professional practice were discussed