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  • 1
    In: Cancer & Metabolism, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2022-12)
    Abstract: Prostate cancer growth is driven by androgen receptor signaling, and advanced disease is initially treatable by depleting circulating androgens. However, prostate cancer cells inevitably adapt, resulting in disease relapse with incurable castrate-resistant prostate cancer. Androgen deprivation therapy has many side effects, including hypercholesterolemia, and more aggressive and castrate-resistant prostate cancers typically feature cellular accumulation of cholesterol stored in the form of cholesteryl esters. As cholesterol is a key substrate for de novo steroidogenesis in prostate cells, this study hypothesized that castrate-resistant/advanced prostate cancer cell growth is influenced by the availability of extracellular, low-density lipoprotein (LDL)-derived, cholesterol, which is coupled to intracellular cholesteryl ester homeostasis. Methods C4-2B and PC3 prostate cancer cells were cultured in media supplemented with fetal calf serum (FCS), charcoal-stripped FCS (CS-FCS), lipoprotein-deficient FCS (LPDS), or charcoal-stripped LPDS (CS-LPDS) and analyzed by a variety of biochemical techniques. Cell viability and proliferation were measured by MTT assay and Incucyte, respectively. Results Reducing lipoprotein availability led to a reduction in cholesteryl ester levels and cell growth in C4-2B and PC3 cells, with concomitant reductions in PI3K/mTOR and p38MAPK signaling. This reduced growth in LPDS-containing media was fully recovered by supplementation of exogenous low-density lipoprotein (LDL), but LDL only partially rescued growth of cells cultured with CS-LPDS. This growth pattern was not associated with changes in androgen receptor signaling but rather increased p38MAPK and MEK1/ERK/MSK1 activation. The ability of LDL supplementation to rescue cell growth required cholesterol esterification as well as cholesteryl ester hydrolysis activity. Further, growth of cells cultured in low androgen levels (CS-FCS) was suppressed when cholesteryl ester hydrolysis was inhibited. Conclusions Overall, these studies demonstrate that androgen-independent prostate cancer cell growth can be influenced by extracellular lipid levels and LDL-cholesterol availability and that uptake of extracellular cholesterol, through endocytosis of LDL-derived cholesterol and subsequent delivery and storage in the lipid droplet as cholesteryl esters, is required to support prostate cancer cell growth. This provides new insights into the relationship between extracellular cholesterol, intracellular cholesterol metabolism, and prostate cancer cell growth and the potential mechanisms linking hypercholesterolemia and more aggressive prostate cancer.
    Type of Medium: Online Resource
    ISSN: 2049-3002
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
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  • 2
    In: Genetics in Medicine, Elsevier BV, Vol. 23, No. 2 ( 2021-02), p. 306-315
    Type of Medium: Online Resource
    ISSN: 1098-3600
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2021
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    SSG: 12
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  • 3
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 5883-5883
    Abstract: Ovarian cancer (OC) is the leading cause of gynecologic cancer-related deaths due to late diagnosis and chemoresistance. RNA-seq data, conducted in collaboration with our group, compared the expression of transcription levels between normal Fallopian tube and high-grade serous ovarian carcinoma samples and revealed phosphodiesterase 7-A as a novel potential therapeutic target against the disease. Metabolic cell viability assays (MCV) were conducted following OC cells treatment with selective PDE7 inhibitor (BRL50481) in monotherapy or in association with paclitaxel (PTX). Mechanism of action of the drug was evaluated by cell cycle analysis, anexina V/PI assay, immunoblotting, real-time PCR and scanning/transmission electron microscopy. Data showed that the use of the BRL50481 in monotherapy reduced A2780 cells MCV by ~60% in a dose-dependent manner after 48h treatment, but nothing significant was observed in OVCAR3. On the other hand, the association of BRL50481 and PTX promoted inhibition of MCV in both cell lines analyzed. An increase in the potency of PTX was also observed, an aspect verified with the reduction of its IC50 in relation to monotherapy by 30% (p & lt;0.01). Treatment chronology in cell survival was also verified. Thus, pretreatment of A2780 with BRL50481 200μM followed by its association with PTX promoted a reduction in cells MCV of ~70% (p & lt;0.01) compared to treatment with PTX alone. With regard to OVCAR3, 400μM pretreatment of BRL50481 provided a VCM reduction of ~20% (p & lt;0.001). Therefore, our results showed beneficial effect between the combination of PDE7 inhibitor and PTX, which allowed reduction of the PTX concentration used in A2780 and OVCAR3 by ~82.7 x 108 and 80.4 x 103uM, respectively. Moreover, the combination of BRL50481 and PTX promoted increased cell necrosis in OVCAR3. In addition, pretreatment of OVCAR3 with BRL50481 modulated the gene expression of the cytokines, as well as increased IL-6 secretion. The combination of BRL50481 and PTX further modulated negatively the PI3K/AKT/mTOR signaling pathway in both cell lines studied. Furthermore, the A2780-pretreated cells showed an increase in the expression of the pro-apoptotic Bax protein. Still, cell death may be related to the induction of autophagy seen in both by the increase of the expression of beclin. Moreover, BRL50481 promoted changes in OC cellular morphology, resembling the induction of cell death by BRL50481, as well as mitochondria and mitochondrial cristae modification. The association of the PDE7 inhibitor with PTX has been proved potentially beneficial in the fight against OC. The impressive additive effect between the drugs allows us to postulate a substantial decrease in PTX neurotoxicity caused in patients by the drug. Our current challenge is to synthesize less toxic BRL50481 analogues, which is only approved for experimental purposes, hence providing hope for better life quality to OC patients. Citation Format: Nayara G. Tessarollo, Isabella S. Guimarães, Diandra Z. dos Santos, Taciane B. Henriques, Marcele LM Souza, Laura Maciel, João Carlos A. Almeida, Alan Branco, Ian V. Silva, Leticia BA Rangel. Phosphodiesterase 7-A is a novel potential therapeutic target against ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5883.
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2018
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    detail.hit.zdb_id: 410466-3
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  • 4
    Online Resource
    Online Resource
    American Association for Cancer Research (AACR) ; 2023
    In:  Cancer Research Vol. 83, No. 11_Supplement ( 2023-06-02), p. B073-B073
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 83, No. 11_Supplement ( 2023-06-02), p. B073-B073
    Abstract: Background: A major challenge in the clinical management of prostate cancer (PCa) is inhibiting progression to lethal castrate-resistant PC (CRPC). Deregulated activity of mevalonate (MVA), cholesterol biosynthetic pathway is a recognized hallmark of PCa cells. Statins are potent inhibitors of this metabolic pathway that have been used for decades in the control of hypercholesterolemia. Statins have recently been shown to have anti-PCa activity, however statin treatment triggers a feedback response that restores the MVA pathway, which reduces statin efficacy and contributes to resistance. This restorative feedback loop is controlled by the transcriptional activity of sterol regulatory-element binding protein (SREBP), which primarily induces fatty acid biosynthesis and MVA pathway genes. We have recently identified the anti-platelet agent dipyridamole (DP) as an inhibitor of the statin-induced SREBP-mediated feedback response. However, DP is not SREBP-specific and given its anti-platelet activity, may not be suitable for every cancer patient. Thus, our goal was to identify additional drugs that potentiate the pro-apoptotic activity of statins, which can be used to treat PCa patients. Methods: Two independent, yet complimentary strategies were used. The first focused on performing an in silico analysis to identify drugs that had similar properties to DP at the level of drug structure, molecular perturbations and cell line sensitivity. The second strategy involved a high-content imaging analysis of 1508 FDA approved drugs, which was performed in LNCaP (relatively statin insensitive and feedback competent) and PC3 cells (statin sensitive and feedback incompetent). Cells were treated with a sub-lethal dose of fluvastatin, the drugs or the fluvastatin-drug combination, then treated with apoptotic stains (TMRE, Annexin, Draq 5). Captured images were analyzed using a machine learning approach. Results: Validation of hits from the in silico MVA-DNF approach and high-content screening has identified several drugs that fulfill our criteria of potentiating statin-induced cell death in a feedback-dependent or feedback-independent manner. Interestingly, many show higher Z-scores compared to DP indicating their superior statin potentiation activity to drive PCa cell death. Moreover, a sub-set of these drug significantly inhibit statin-triggered expression of MVA pathway genes HMGCS1 and INSIG1 (p & lt; 0.001) more potently than DP. Conclusions: We have detailed two successful strategies to identify drugs that inhibit SREBP activation in response to statin treatment. These statin-drug combinations represent an effective ‘one-two punch’ to inhibit CRPC progression. These novel inhibitors of SREBP activation potentiate statin at clinically relevant concentrations more potently than DP and have no effect on the platelet activity. Excitingly, many of these agents are FDA-approved and can be immediately used in combination with statins for the treatment of PCa. Overall, our research will lead to novel therapies to improve patient outcome. Citation Format: Diandra Zipinotti dos Santos, Mohamad Elbaz, Emily Branchard, Wiebke Schormann, David W. Andrews, Linda Z. Penn. Inhibiting prostate cancer by targeting the metabolic mevalonate pathway [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B073.
    Type of Medium: Online Resource
    ISSN: 1538-7445
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2023
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    detail.hit.zdb_id: 410466-3
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