| 1. |
- Bovinder Ylitalo, Erik, et al.
(författare)
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A novel DNA methylation signature is associated with androgen receptor activity and patient prognosis in bone metastatic prostate cancer
- 2021
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Ingår i: Clinical Epigenetics. - : BioMed Central. - 1868-7083 .- 1868-7075. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with metastatic prostate cancer (PC) are treated with androgen deprivation therapy (ADT) that initially reduces metastasis growth, but after some time lethal castration-resistant PC (CRPC) develops. A better understanding of the tumor biology in bone metastases is needed to guide further treatment developments. Subgroups of PC bone metastases based on transcriptome profiling have been previously identified by our research team, and specifically, heterogeneities related to androgen receptor (AR) activity have been described. Epigenetic alterations during PC progression remain elusive and this study aims to explore promoter gene methylation signatures in relation to gene expression and tumor AR activity.Materials and methods: Genome-wide promoter-associated CpG methylation signatures of a total of 94 tumor samples, including paired non-malignant and malignant primary tumor areas originating from radical prostatectomy samples (n = 12), and bone metastasis samples of separate patients with hormone-naive (n = 14), short-term castrated (n = 4) or CRPC (n = 52) disease were analyzed using the Infinium Methylation EPIC arrays, along with gene expression analysis by Illumina Bead Chip arrays (n = 90). AR activity was defined from expression levels of genes associated with canonical AR activity.Results: Integrated epigenome and transcriptome analysis identified pronounced hypermethylation in malignant compared to non-malignant areas of localized prostate tumors. Metastases showed an overall hypomethylation in relation to primary PC, including CpGs in the AR promoter accompanied with induction of AR mRNA levels. We identified a Methylation Classifier for Androgen receptor activity (MCA) signature, which separated metastases into two clusters (MCA positive/negative) related to tumor characteristics and patient prognosis. The MCA positive metastases showed low methylation levels of genes associated with canonical AR signaling and patients had a more favorable prognosis after ADT. In contrast, MCA negative patients had low AR activity associated with hypermethylation of AR-associated genes, and a worse prognosis after ADT.Conclusions: A promoter methylation signature classifies PC bone metastases into two groups and predicts tumor AR activity and patient prognosis after ADT. The explanation for the methylation diversities observed during PC progression and their biological and clinical relevance need further exploration.
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| 2. |
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| 3. |
- Bovinder Ylitalo, Erik, et al.
(författare)
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Marked response to cabazitaxel in prostate cancer xenografts expressing androgen receptor variant 7 and reversion of acquired resistance by anti-androgens
- 2020
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Ingår i: Prostate. - : Wiley. - 0270-4137 .- 1097-0045. ; 80:1, s. 214-224
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Tidskriftsartikel (refereegranskat)abstract
- Background Taxane treatment may be a suitable therapeutic option for patients with castration-resistant prostate cancer and high expression of constitutively active androgen receptor variants (AR-Vs). The aim of the study was to compare the effects of cabazitaxel and androgen deprivation treatments in a prostate tumor xenograft model expressing high levels of constitutively active AR-V7. Furthermore, mechanisms behind acquired cabazitaxel resistance were explored. Methods Mice were subcutaneously inoculated with 22Rv1 cells and treated with surgical castration (n = 7), abiraterone (n = 9), cabazitaxel (n = 6), castration plus abiraterone (n = 8), castration plus cabazitaxel (n = 11), or vehicle and/or sham operation (n = 23). Tumor growth was followed for about 2 months or to a volume of approximately 1000 mm(3). Two cabazitaxel resistant cell lines; 22Rv1-CabR1 and 22Rv1-CabR2, were established from xenografts relapsing during cabazitaxel treatment. Differential gene expression between the cabazitaxel resistant and control 22Rv1 cells was examined by whole-genome expression array analysis followed by immunoblotting, immunohistochemistry, and functional pathway analysis. Results Abiraterone treatment alone or in combination with surgical castration had no major effect on 22Rv1 tumor growth, while cabazitaxel significantly delayed and in some cases totally abolished 22Rv1 tumor growth on its own and in combination with surgical castration. The cabazitaxel resistant cell lines; 22Rv1-CabR1 and 22Rv1-CabR2, both showed upregulation of the ATP-binding cassette sub-family B member 1 (ABCB1) efflux pump. Treatment with ABCB1 inhibitor elacridar completely restored susceptibility to cabazitaxel, while treatment with AR-antagonists bicalutamide and enzalutamide partly restored susceptibility to cabazitaxel in both cell lines. The cholesterol biosynthesis pathway was induced in the 22Rv1-CabR2 cell line, which was confirmed by reduced sensitivity to simvastatin treatment. Conclusions Cabazitaxel efficiently inhibits prostate cancer growth despite the high expression of constitutively active AR-V7. Acquired cabazitaxel resistance involving overexpression of efflux transporter ABCB1 can be reverted by bicalutamide or enzalutamide treatment, indicating the great clinical potential for combined treatment with cabazitaxel and anti-androgens.
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| 4. |
- Bovinder Ylitalo, Erik, 1985-
(författare)
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Molecular heterogeneity of prostate cancer bone metastasis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Castration-resistant prostate cancer (CRPC) develops after androgen deprivation therapy of advanced PC, often with metastatic growth in bone. Patients with metastatic CRPC have very poor prognosis. Growth of CRPC, in most but not all patients, seems to involve androgen receptor (AR) activity, despite castrate levels of serum testosterone. Multiple mechanisms behind AR activation in castrated patients have been described, such as AR amplification, AR mutations, expression of constitutively active AR variants, and intra-tumoral steroid synthesis. However, other mechanisms beside AR activation are also involved and CRPC patients with tumors circumventing the need for AR stimulation will probably not benefit from AR targeting therapies but will need alternative treatments.Available treatments for CRPC are chemotherapy, AR antagonists or inhibition of androgen-synthesis. Novel drugs are constantly under development and several new therapies has recently been approved for clinical use. These include, in addition to new AR targeting therapies also immunotherapy, osteoclast inhibitors and bone-targeting radiopharmaceuticals. Due to heterogeneous mechanisms behind CRPC and that newly developed therapies are based on different mechanisms of action, there are reasons to believe that CRPC patients show different therapy responses due to diverse molecular properties of individual tumors. Although there are promising prospects, no biomarkers are used today for patient stratification into different treatments. Another important aspect is that, when effective, any therapy will probably induce tumor responses that subsequently cause further molecular diversities and alternative paths for development of tumor relapse and castration-resistance. Such mechanisms are important to understand in order to develop new treatment strategies.In this thesis, global gene expression and methylation patterns were studied in bone metastases obtained from PC patients going through metastasis surgery for spinal cord compression. Gene expression patterns were analyzed by multivariate statistics and ontology analysis with the aim to identify subgroups of biological/pathological relevance. Interesting findings from array analysis were verified using qRT-PCR and immunohistochemical analysis. In addition, a xenograft mouse model was used to study the effects of abiraterone (steroidogenesis inhibitor) and cabazitaxel (taxane), and subsequently developed resistance mechanisms in the 22Rv1 PC cell line expressing high levels of AR-V7; a constitutively active AR splice variant associated with a poor prognosis and resistance to AR targeting therapies.In summary, results showed that the majority of CRPC bone metastases were AR-driven, defined from high levels of AR-regulated gene transcripts, while a smaller sub-group was non-AR-driven (paper I). AR-driven bone metastases had high metabolic activity in combination with downregulated immune responses while non-AR-driven cases had a more pronounced immune response (paper I) and higher bone cell activity (paper II). Paper III identified pronounced hypermethylation in primary prostate tumors probably causing a suppressed anti-tumor immune-response whereas metastases showed a different methylation pattern related to increased AR activity and patient outcome. In paper IV, 22Rv1 xenografts showed poor response to abiraterone and initially excellent response to cabazitaxel, but eventually resistance occurred probably due to an upregulation of the ABCB1 transporter protein. Anti-androgens partly reversed the resistance.In conclusion, we have identified molecular heterogeneities in clinical bone metastases associated with biological characteristics, which could perhaps be used both for stratifying patients into treatment modalities, and to aid in further development of effective therapies for CRPC.
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| 6. |
- Brattsand, Maria
(författare)
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Doxycycline at Low Concentrations Could Influence Your Experimental Results When Working With Prostate Cancer Cell Lines
- 2020
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Ingår i: Biomedical Journal of Scientific & Technical Research. - : Biomedical Research Network. - 2574-1241. ; 28:2, s. 21515-21519
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Tidskriftsartikel (refereegranskat)abstract
- Doxycycline is a tetracycline derivate commonly used in various inducible expression systems to study the function of different proteins. In this study, we show that 22Rv1 and PC3, two different, commonly used prostate cancer cell lines are very sensitive to this antibiotic and addition of the drug at inductive concentrations can affect cells in ways that can be misinterpreted as effects from the protein studied. Therefore, proper controls are very important in order to avoid conclusions drawn by artifacts caused by experimental conditions.
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| 7. |
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| 8. |
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| 9. |
- Brattsand, Maria
(författare)
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Missing factors in human skin equivalent models?
- 2017
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 176:1, s. 11-12
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Recension (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Brattsand, Maria, et al.
(författare)
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Purification and characterization of interleukin 1 beta from human plantar stratum corneum. Evidence of interleukin 1 beta processing in vivo not involving interleukin 1 beta convertase
- 1998
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Ingår i: Cytokine. - : Academic Press. - 1043-4666 .- 1096-0023. ; 10:7, s. 506-513
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Tidskriftsartikel (refereegranskat)abstract
- The major interleukin 1 beta (IL-1 beta) species from human plantar stratum corneum was purified and found to have an N-terminal amino acid sequence homologous to a stretch of the human IL-1 beta precursor, starting with His115. Whereas SDS-polyacrylamide gel electrophoresis followed by immunoblotting revealed only one component in plantar stratum corneum with IL-1 beta-like immunoreactivity, and with an apparent molecular mass around 18 kDa, isoelectric focusing under non-denaturing conditions showed one major component with isoelectric point around 6.1 and two minor components isoelectric at pH 6.3 and 6.9, respectively. Digestion of recombinant human IL-1 beta precursor with chymotrypsin, producing a C-terminal fragment with N-terminal Yal114, yielded a component with IL-1 beta-like immunoreactivity isoelectric at pH 6.3. Recombinant bacterial variants of human IL-1 beta with N-terminal amino acids corresponding to Val114, His115 and Ala117 were isoelectric at pH 6.3, 6.1 and 6.9, respectively. Cloning and subsequent nucleotide sequencing of IL-1 beta precursor cDNA from a human keratinocyte line showed total identify with the sequence previously published for the human monocyte IL-1 beta precursor. The authors conclude that the IL-1 beta species present in plantar stratum corneum have isoelectric points determined by their respective amino acid sequences, and that there is a mechanism for IL-1 beta activation in human epidermis not involving interleukin 1 beta convertase.
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