Pharmacological polyamine catabolism upregulation with methionine salvage pathway inhibition as an effective prostate cancer therapy

AbstractProstatic luminal epithelial cells secrete high levels of acetylated polyamines into the prostatic lumen, sensitizing them to perturbations of connected metabolic pathways. Enhanced flux is driven by spermidine/spermine N1-acetyltransferase (SSAT) activity, which acetylates polyamines leading to their secretion and drives biosynthetic demand. The methionine salvage pathway recycles one-carbon units lost to polyamine biosynthesis to the methionine cycle to overcome stress. Prostate cancer (CaP) relies on methylthioadenosine phosphorylase (MTAP), the rate-limiting enzyme, to relieve strain. Here, we show that inhibition of MTAP alongside SSAT upregulation is synergistic in androgen sensitive and castration recurrent CaP models in vitro and in vivo. The combination treatment increases apoptosis in radical prostatectomy ex vivo explant samples. This unique high metabolic flux through polyamine biosynthesis and connected one carbon metabolism in CaP creates a metabolic dependency. Enhancing this flux while simultaneously targeting this dependency in prostate cancer results in an effective therapeutic approach potentially translatable to the clinic.

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Conditionally Reprogrammed Cells from Patient-Derived Xenograft to Model Neuroendocrine Prostate Cancer Development

Cells ◽

10.3390/cells9061398 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1398 ◽

Cited By ~ 2

Author(s):

Xinpei Ci ◽

Jun Hao ◽

Xin Dong ◽

Hui Xue ◽

Rebecca Wu ◽

...

Keyword(s):

Prostate Cancer ◽

Ex Vivo ◽

Cancer Cell Line ◽

Marker Genes ◽

Patient Derived Xenograft ◽

Pdx Model ◽

Neuroendocrine Prostate Cancer ◽

Parental Tumor

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer. It develops mainly via NE transdifferentiation of prostate adenocarcinoma in response to androgen receptor (AR)-inhibition therapy. The study of NEPC development has been hampered by a lack of clinically relevant models. We previously established a unique and first-in-field patient-derived xenograft (PDX) model of adenocarcinoma (LTL331)-to-NEPC (LTL331R) transdifferentiation. In this study, we applied conditional reprogramming (CR) culture to establish a LTL331 PDX-derived cancer cell line named LTL331_CR_Cell. These cells retain the same genomic mutations as the LTL331 parental tumor. They can be continuously propagated in vitro and can be genetically manipulated. Androgen deprivation treatment on LTL331_CR_Cells had no effect on cell proliferation. Transcriptomic analyses comparing the LTL331_CR_Cell to its parental tumor revealed a profound downregulation of the androgen response pathway and an upregulation of stem and basal cell marker genes. The transcriptome of LTL331_CR_Cells partially resembles that of post-castrated LTL331 xenografts in mice. Notably, when grafted under the renal capsules of male NOD/SCID mice, LTL331_CR_Cells spontaneously gave rise to NEPC tumors. This is evidenced by the histological expression of the NE marker CD56 and the loss of adenocarcinoma markers such as PSA. Transcriptomic analyses of the newly developed NEPC tumors further demonstrate marked enrichment of NEPC signature genes and loss of AR signaling genes. This study provides a novel research tool derived from a unique PDX model. It allows for the investigation of mechanisms underlying NEPC development by enabling gene manipulations ex vivo and subsequent functional evaluations in vivo.

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The methionine salvage pathway in relation to ethylene and polyamine biosynthesis

Physiologia Plantarum ◽

10.1111/j.1399-3054.1987.tb04302.x ◽

1987 ◽

Vol 69 (2) ◽

pp. 366-370 ◽

Cited By ~ 98

Author(s):

John H. Miyazaki ◽

Shang Fa Yang

Keyword(s):

Salvage Pathway ◽

Polyamine Biosynthesis ◽

Methionine Salvage Pathway ◽

Methionine Salvage

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Leveraging RB status to define therapy for castrate-resistant prostate cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.4_suppl.96 ◽

2014 ◽

Vol 32 (4_suppl) ◽

pp. 96-96

Author(s):

Renee de Leeuw ◽

Clay de Comstock ◽

Daniela de Pollutri ◽

Matthew Joseph Schiewer ◽

Stephen J Ciment ◽

...

Keyword(s):

Prostate Cancer ◽

Kinase Inhibitors ◽

Ex Vivo ◽

Tissue Samples ◽

Ki67 Staining ◽

Cell Architecture ◽

Castrate Resistant Prostate Cancer ◽

Castrate Resistant

96 Background: Loss of retinoblastoma (RB) tumor suppressor is overrepresented in castrate-resistant prostate cancer (CRPC) compared to primary PCa. We previously showed using analyses of human tissue and in vitro and in vivo modeling that RB constrains androgen receptor (AR) function, and that loss of RB is sufficient promote resistance to castration and AR antagonists. Thus, novel strategies are needed to treat RB-deficient tumor. By contrast, in tumors retaining RB, suppressing enhancing RB activity would be of therapeutic advantage, and may be accomplished through next-generation Cdk4/6 inhibitors. Methods: Stable isogenic pairs of prostate cancer cell lines either retaining RB or RB depleted (by shRNA) were assessed in vitro and in xenografts for response to Cdk4/6 kinase inhibitors or the cabazitaxel. In addition, using an ex vivo explant assay, fresh tumor tissue samples from radical prostatectomy were exposed to the Cdk4/6 inhibitor or cabazitaxel for up to 7 days, and evaluated by IHC for Ki67, Caspase-3, and AR. Results: Cdk4/6 inhibition blocks tumor cell proliferation dependent on RB status. This was further confirmed ex vivo, as evidenced by a marked reduction in Ki67 staining in Cdk4/6 inhibitor treated explant tissue from two prostate cancer patients. Conversely, in vitro studies revealed a modest sensitization of RB-depleted tumors to cabazitaxel that was dramatically enhanced in vivo and after castration. Cabazitaxel, like docetaxel, targets the cell architecture and induces cell death, but also induces a distinct gene expression profile that may partially explain efficacy in docetaxel-resistant tumors. Neither taxane showed affects on AR nuclear localization using in vivoor explant studies. Conclusions: These results strongly support our hypothesis that RB status can be used as a metric to define therapeutic response to cabazitaxel, as such that loss of RB function induces sensitization taxanes, whereas RB proficient tumors give an enhanced response to Cdk4/6 kinase inhibitors.

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MINDIN secretion by prostate tumors induces premetastatic changes in bone via β-catenin

Endocrine Related Cancer ◽

10.1530/erc-20-0116 ◽

2020 ◽

Vol 27 (7) ◽

pp. 441-456

Author(s):

Juan A Ardura ◽

Luis Álvarez-Carrión ◽

Irene Gutiérrez-Rojas ◽

Peter A Friedman ◽

Arancha R Gortázar ◽

...

Keyword(s):

Gene Expression ◽

Prostate Cancer ◽

Tumor Cell ◽

Ex Vivo ◽

Prostate Tumor ◽

Tumor Cell Adhesion ◽

Prostate Tumors ◽

Cell Homing

Bone metastases are common in advanced prostate cancer patients, but mechanisms by which specific pro-metastatic skeletal niches are formed before tumor cell homing are unclear. We aimed to analyze the effects of proteins secreted by primary prostate tumors on the bone microenvironment before the settlement and propagation of metastases. Here, using an in vivo pre-metastatic prostate cancer model based on the implantation of prostate adenocarcinoma TRAMP-C1 cells in immunocompetent C57BL/6 mice, we identify MINDIN as a prostate tumor secreted protein that induces bone microstructural and bone remodeling gene expression changes before tumor cell homing. Associated with these changes, increased tumor cell adhesion to the endosteum ex vivo and to osteoblasts in vitro was observed. Furthermore, MINDIN promoted osteoblast proliferation and mineralization and monocyte expression of osteoclast markers. β-catenin signaling pathway revealed to mediate MINDIN actions on osteoblast gene expression but failed to affect MINDIN-induced adhesion to prostate tumor cells or monocyte differentiation to osteoclasts. Our study evidences that MINDIN secretion by primary prostate tumors creates a favorable bone environment for tumor cell homing before metastatic spread.

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Phase I trial of anti-PSMA designer T-cell autografting in prostate cancer

Journal of Clinical Oncology ◽

10.1200/jco.2009.27.15_suppl.e16132 ◽

2009 ◽

Vol 27 (15_suppl) ◽

pp. e16132-e16132

Author(s):

M. Abedi ◽

Q. Ma ◽

A. Bais ◽

E. Gomes ◽

E. Beaudoin ◽

...

Keyword(s):

Prostate Cancer ◽

Clinical Trial ◽

T Cells ◽

T Cell ◽

Phase I ◽

Ex Vivo ◽

Immune Therapy ◽

Us Army

e16132 Background: We created chimeric immunoglobulin-T cell receptors (IgTCR) specific for prostate specific membrane antigen (PSMA). When expressed in patient T cells, these “designer T cells” specifically kill prostate cancer cells in vitro and in vivo in animal models, with 5/9 (55%) of xenografted mice experiencing complete remissions (Ma et al. Prostate 2004:61:12–25). A Phase I clinical trial was approved by the FDA in metastatic prostate cancers. Methods: Patient T cells are retrovirally transduced and expanded ex vivo to span dose levels of 10^9 to 10^11 T cells. Adapting methods of Dudley, Rosenberg and colleagues, patients undergo prior non-myeloablative (NMA) conditioning to create a “hematologic space” into which the infused designer T cells will stably engraft for prolonged in vivo efficacy. Patients are co-administered continuous infusion IL2. Outcomes will include Phase Ia goals of safety and toxicity and Phase Ib goals of establishing an optimal biologic dose in terms of designer T cell engraftment and tumor response. Results: For the first two patients, excellent T cell modifications of 50–60% were obtained. After NMA conditioning, T cells were infused and stable engraftments of 1–5% were observed post recovery, even at this lowest 10^9 T cell dose level, thus affirming one of the study end-points. The patients had PSA reductions of 50 and 70% in the two months following treatment. Patients experienced neutropenia and lymphopenia after conditioning, but no designer T cell-related toxicities. Results with additional patients will be described in terms of safety, engraftment efficiency and tumor responses. Conclusions: A new approach to adoptive immune therapy in metastatic prostate cancer has been devised. This clinical trial is funded by the US Army/DOD. No significant financial relationships to disclose.

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The circadian cryptochrome, CRY1, is a pro-tumorigenic factor that rhythmically modulates DNA repair

Nature Communications ◽

10.1038/s41467-020-20513-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Ayesha A. Shafi ◽

Chris M. McNair ◽

Jennifer J. McCann ◽

Mohammed Alshalalfa ◽

Anton Shostak ◽

...

Keyword(s):

Prostate Cancer ◽

Dna Damage ◽

Dna Repair ◽

Ex Vivo ◽

Functional Studies ◽

Expression Of Genes ◽

Mechanistic Investigation ◽

Transcriptional Coregulator

AbstractMechanisms regulating DNA repair processes remain incompletely defined. Here, the circadian factor CRY1, an evolutionally conserved transcriptional coregulator, is identified as a tumor specific regulator of DNA repair. Key findings demonstrate that CRY1 expression is androgen-responsive and associates with poor outcome in prostate cancer. Functional studies and first-in-field mapping of the CRY1 cistrome and transcriptome reveal that CRY1 regulates DNA repair and the G2/M transition. DNA damage stabilizes CRY1 in cancer (in vitro, in vivo, and human tumors ex vivo), which proves critical for efficient DNA repair. Further mechanistic investigation shows that stabilized CRY1 temporally regulates expression of genes required for homologous recombination. Collectively, these findings reveal that CRY1 is hormone-induced in tumors, is further stabilized by genomic insult, and promotes DNA repair and cell survival through temporal transcriptional regulation. These studies identify the circadian factor CRY1 as pro-tumorigenic and nominate CRY1 as a new therapeutic target.

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Cholesterol-Based Nanovesicles Enhance the In Vitro Cytotoxicity, Ex Vivo Intestinal Absorption, and In Vivo Bioavailability of Flutamide

Pharmaceutics ◽

10.3390/pharmaceutics13111741 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1741

Author(s):

Mohamed A. Ali ◽

Magdy I. Mohamed ◽

Mohamed A. Megahed ◽

Tamer M. Abdelghany ◽

Khalid M. El-Say

Keyword(s):

Prostate Cancer ◽

Adverse Effects ◽

Cell Line ◽

Oral Bioavailability ◽

Ex Vivo ◽

Cancer Cell Line ◽

In Vitro Cytotoxicity ◽

Rabbit Intestine

Critical adverse effects and frequent administration, three times per day, limit the use of flutamide (FLT) as a chemotherapeutic agent in the treatment of prostate cancer. Therefore, our research aimed to develop new cholesterol-based nanovesicles for delivering FLT to malignant cells in an endeavor to maximize its therapeutic efficacy and minimize undesired adverse effects. Draper–Lin small composite design was used to optimize the critical quality attributes of FLT-loaded niosomes and ensure the desired product quality. The influence of the selected four independent variables on mean particle size (Y1), zeta potential (Y2), drug entrapment efficiency (Y3), and the cumulative drug release after 24 h (Y4) was examined. The optimized nanovesicles were assessed for their in vitro cytotoxicity, ex-vivo absorption via freshly excised rabbit intestine as well as in vivo pharmacokinetics on male rats. TEM confirmed nanovescicles’ spherical shape with bilayer structure. Values of dependent variables were 748.6 nm, −48.60 mV, 72.8% and 72.2% for Y1, Y2, Y3 and Y4, respectively. The optimized FLT-loaded niosomes exerted high cytotoxic efficacy against human prostate cancer cell line (PC-3) with an IC50 value of 0.64 ± 0.04 µg/mL whilst, it was 1.88 ± 0.16 µg/mL for free FLT. Moreover, the IC50 values on breast cancer cell line (MCF-7) were 0.27 ± 0.07 µg/mL and 4.07 ± 0.74 µg/mL for FLT-loaded niosomes and free FLT, respectively. The permeation of the optimized FLT-loaded niosomes through the rabbit intestine showed an enhancement ratio of about 1.5 times that of the free FLT suspension. In vivo pharmacokinetic study displayed an improvement in oral bioavailability of the optimized niosomal formulation with AUC and Cmax values of 741.583 ± 33.557 μg/mL × min and 6.950 ± 0.45 μg/mL compared to 364.536 ± 45.215 μg/mL × min and 2.650 ± 0.55 μg/mL for the oral FLT suspension. With these promising findings, we conclude that encapsulation of FLT in cholesterol-loaded nanovesicles enhanced its anticancer activity and oral bioavailability which endorse its use in the management of prostate cancer.

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PI3K-AKT-mTOR Pathway is Dominant over Androgen Receptor Signaling in Prostate Cancer Cells

Analytical Cellular Pathology ◽

10.1155/2010/290643 ◽

2010 ◽

Vol 32 (1-2) ◽

pp. 11-27

Author(s):

Mari Kaarbø ◽

Øyvind Løveseter Mikkelsen ◽

Lene Malerød ◽

Su Qu ◽

Viola H. Lobert ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Growth ◽

Cancer Cells ◽

Molecular Mechanisms ◽

Pi3k Pathway ◽

Prostate Cancer Cells ◽

Pathway Inhibition

Background: Androgen receptor (AR) and the phosphatidylinositol-3 kinase (PI3K) signaling are two of the most important pathways implicated in prostate cancer. Previous work has shown that there is crosstalk between these two pathways; however, there are conflicting findings and the molecular mechanisms are not clear. Here we studied the AR–PI3K pathway crosstalk in prostate cancer cells in vitro as well as in vivo.Methods: Quantitative PCR, Western analysis, reporter assays, and proliferation analyses in vitro and in vivo were used to evaluate the effect of PI3K pathway inhibition on AR signaling and cell growth.Results: Transcriptional activity of AR was increased when the PI3K pathway was inhibited at different levels. In the androgen responsive prostate cancer cell line LNCaP, androgen and the mTOR inhibitor rapamycin synergistically activated androgen target genes. Despite increased androgen signaling, rapamycin treatment reduced LNCaP cell growth; the AR antagonist bicalutamide potentiated this effect. Furthermore, the rapamycin derivative CCI-779 reduced the growth of CWR22 prostate cancer xenografts while increasing AR target gene expression.Conclusions: These findings suggest that inhibition of the PI3K pathway activates AR signaling. Despite the increase in AR signaling which has proliferative effects, the result of PI3K pathway inhibition is antiproliferative. These findings suggest that the PI3K pathway is dominant over AR signaling in prostate cancer cells which should be considered in developing novel therapeutic strategies for prostate cancer.

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Computational modeling identifies multitargeted kinase inhibitors as effective therapies for metastatic, castration-resistant prostate cancer

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2103623118 ◽

2021 ◽

Vol 118 (40) ◽

pp. e2103623118

Author(s):

Thomas Bello ◽

Claudia Paindelli ◽

Luis A. Diaz-Gomez ◽

Anthony Melchiorri ◽

Antonios G. Mikos ◽

...

Keyword(s):

Prostate Cancer ◽

Computational Modeling ◽

Late Stage ◽

Kinase Inhibitors ◽

Ex Vivo ◽

Growth Factor Signaling ◽

Castration Resistant Prostate Cancer ◽

Castration Resistant

Castration-resistant prostate cancer (CRPC) is an advanced subtype of prostate cancer with limited therapeutic options. Here, we applied a systems-based modeling approach called kinome regularization (KiR) to identify multitargeted kinase inhibitors (KIs) that abrogate CRPC growth. Two predicted KIs, PP121 and SC-1, suppressed CRPC growth in two-dimensional in vitro experiments and in vivo subcutaneous xenografts. An ex vivo bone mimetic environment and in vivo tibia xenografts revealed resistance to these KIs in bone. Combining PP121 or SC-1 with docetaxel, standard-of-care chemotherapy for late-stage CRPC, significantly reduced tibia tumor growth in vivo, decreased growth factor signaling, and vastly extended overall survival, compared to either docetaxel monotherapy. These results highlight the utility of computational modeling in forming physiologically relevant predictions and provide evidence for the role of multitargeted KIs as chemosensitizers for late-stage, metastatic CRPC.

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